diff --git a/hgext/rebase.py b/hgext/rebase.py
--- a/hgext/rebase.py
+++ b/hgext/rebase.py
@@ -22,6 +22,8 @@ from mercurial.lock import release
 from mercurial.i18n import _
 import os, errno
 
+nullmerge = -2
+
 def rebase(ui, repo, **opts):
     """move changeset (and descendants) to a different branch
 
@@ -53,6 +55,7 @@ def rebase(ui, repo, **opts):
         extrafn = opts.get('extrafn')
         keepf = opts.get('keep', False)
         keepbranchesf = opts.get('keepbranches', False)
+        detachf = opts.get('detach', False)
 
         if contf or abortf:
             if contf and abortf:
@@ -62,6 +65,10 @@ def rebase(ui, repo, **opts):
                 raise error.ParseError(
                     'rebase', _('cannot use collapse with continue or abort'))
 
+            if detachf:
+                raise error.ParseError(
+                    'rebase', _('cannot use detach with continue or abort'))
+
             if srcf or basef or destf:
                 raise error.ParseError('rebase',
                     _('abort and continue do not allow specifying revisions'))
@@ -75,8 +82,16 @@ def rebase(ui, repo, **opts):
             if srcf and basef:
                 raise error.ParseError('rebase', _('cannot specify both a '
                                                    'revision and a base'))
+            if detachf:
+                if not srcf:
+                    raise error.ParseError(
+                      'rebase', _('detach requires a revision to be specified'))
+                if basef:
+                    raise error.ParseError(
+                        'rebase', _('cannot specify a base with detach'))
+
             cmdutil.bail_if_changed(repo)
-            result = buildstate(repo, destf, srcf, basef)
+            result = buildstate(repo, destf, srcf, basef, detachf)
             if not result:
                 # Empty state built, nothing to rebase
                 ui.status(_('nothing to rebase\n'))
@@ -140,10 +155,10 @@ def rebase(ui, repo, **opts):
                                                         state, targetancestors)
             commitmsg = 'Collapsed revision'
             for rebased in state:
-                if rebased not in skipped:
+                if rebased not in skipped and state[rebased] != nullmerge:
                     commitmsg += '\n* %s' % repo[rebased].description()
             commitmsg = ui.edit(commitmsg, repo.ui.username())
-            concludenode(repo, rev, p1, external, commitmsg=commitmsg,
+            newrev = concludenode(repo, rev, p1, external, commitmsg=commitmsg,
                                                     extra=extrafn)
 
         if 'qtip' in repo.tags():
@@ -151,11 +166,13 @@ def rebase(ui, repo, **opts):
 
         if not keepf:
             # Remove no more useful revisions
-            if set(repo.changelog.descendants(min(state))) - set(state):
-                ui.warn(_("warning: new changesets detected on source branch, "
-                                                        "not stripping\n"))
-            else:
-                repair.strip(ui, repo, repo[min(state)].node(), "strip")
+            rebased = [rev for rev in state if state[rev] != nullmerge]
+            if rebased:
+                if set(repo.changelog.descendants(min(rebased))) - set(state):
+                    ui.warn(_("warning: new changesets detected on source branch, "
+                                                            "not stripping\n"))
+                else:
+                    repair.strip(ui, repo, repo[min(rebased)].node(), "strip")
 
         clearstatus(repo)
         ui.status(_("rebase completed\n"))
@@ -260,7 +277,10 @@ def defineparents(repo, rev, target, sta
     if P1n in targetancestors:
         p1 = target
     elif P1n in state:
-        p1 = state[P1n]
+        if state[P1n] == nullmerge:
+            p1 = target
+        else:
+            p1 = state[P1n]
     else: # P1n external
         p1 = target
         p2 = P1n
@@ -379,9 +399,10 @@ def abort(repo, originalwd, target, stat
         clearstatus(repo)
         repo.ui.status(_('rebase aborted\n'))
 
-def buildstate(repo, dest, src, base):
+def buildstate(repo, dest, src, base, detach):
     'Define which revisions are going to be rebased and where'
     targetancestors = set()
+    detachset = set()
 
     if not dest:
         # Destination defaults to the latest revision in the current branch
@@ -400,6 +421,12 @@ def buildstate(repo, dest, src, base):
         if commonbase == repo[dest]:
             raise util.Abort(_('source is descendant of destination'))
         source = repo[src].rev()
+        if detach:
+            # We need to keep track of source's ancestors up to the common base
+            srcancestors = set(repo.changelog.ancestors(source))
+            baseancestors = set(repo.changelog.ancestors(commonbase.rev()))
+            detachset = srcancestors - baseancestors
+            detachset.remove(commonbase.rev())
     else:
         if base:
             cwd = repo[base].rev()
@@ -426,6 +453,7 @@ def buildstate(repo, dest, src, base):
 
     repo.ui.debug('rebase onto %d starting from %d\n' % (dest, source))
     state = dict.fromkeys(repo.changelog.descendants(source), nullrev)
+    state.update(dict.fromkeys(detachset, nullmerge))
     state[source] = nullrev
     return repo['.'].rev(), repo[dest].rev(), state
 
@@ -468,9 +496,11 @@ cmdtable = {
         ('', 'collapse', False, _('collapse the rebased changesets')),
         ('', 'keep', False, _('keep original changesets')),
         ('', 'keepbranches', False, _('keep original branch names')),
+        ('', 'detach', False, _('force detaching of source from its original '
+                                'branch')),
         ('c', 'continue', False, _('continue an interrupted rebase')),
         ('a', 'abort', False, _('abort an interrupted rebase')),] +
          templateopts,
-        _('hg rebase [-s REV | -b REV] [-d REV] [--collapse] [--keep] '
-                            '[--keepbranches] | [-c] | [-a]')),
+        _('hg rebase [-s REV | -b REV] [-d REV] [--collapse] [--detach] '
+                        '[--keep] [--keepbranches] | [-c] | [-a]')),
 }
diff --git a/tests/test-rebase-detach b/tests/test-rebase-detach
new file mode 100755
--- /dev/null
+++ b/tests/test-rebase-detach
@@ -0,0 +1,68 @@
+#!/bin/sh
+
+echo "[extensions]" >> $HGRCPATH
+echo "graphlog=" >> $HGRCPATH
+echo "rebase=" >> $HGRCPATH
+
+BASE=`pwd`
+
+addcommit () {
+    echo $1 > $1
+    hg add $1
+    hg commit -d "${2} 0" -m $1
+}
+
+commit () {
+    hg commit -d "${2} 0" -m $1
+}
+
+createrepo () {
+    cd $BASE
+    rm -rf a
+    hg init a
+    cd a
+    addcommit "A" 0
+    addcommit "B" 1
+    addcommit "C" 2
+    addcommit "D" 3
+
+    hg update -C 0
+    addcommit "E" 4
+}
+
+createrepo > /dev/null 2>&1
+hg glog  --template '{rev}: {desc}\n'
+echo '% Rebasing D onto E detaching from C'
+hg rebase --detach -s 3 -d 4 2>&1 | sed 's/\(saving bundle to \).*/\1/'
+hg glog  --template '{rev}: {desc}\n'
+echo "Expected A, D, E"
+hg manifest
+
+echo
+createrepo > /dev/null 2>&1
+hg glog  --template '{rev}: {desc}\n'
+echo '% Rebasing C onto E detaching from B'
+hg rebase --detach -s 2 -d 4 2>&1 | sed 's/\(saving bundle to \).*/\1/'
+hg glog  --template '{rev}: {desc}\n'
+echo "Expected A, C, D, E"
+hg manifest
+
+echo
+createrepo > /dev/null 2>&1
+hg glog  --template '{rev}: {desc}\n'
+echo '% Rebasing B onto E using detach (same as not using it)'
+hg rebase --detach -s 1 -d 4 2>&1 | sed 's/\(saving bundle to \).*/\1/'
+hg glog  --template '{rev}: {desc}\n'
+echo "Expected A, B, C, D, E"
+hg manifest
+
+echo
+createrepo > /dev/null 2>&1
+hg glog  --template '{rev}: {desc}\n'
+echo '% Rebasing C onto E detaching from B and collapsing'
+hg rebase --detach --collapse -s 2 -d 4 2>&1 | sed 's/\(saving bundle to \).*/\1/'
+hg glog  --template '{rev}: {desc}\n'
+echo "Expected A, C, D, E"
+hg manifest
+
+exit 0
diff --git a/tests/test-rebase-detach.out b/tests/test-rebase-detach.out
new file mode 100644
--- /dev/null
+++ b/tests/test-rebase-detach.out
@@ -0,0 +1,134 @@
+@  4: E
+|
+| o  3: D
+| |
+| o  2: C
+| |
+| o  1: B
+|/
+o  0: A
+
+% Rebasing D onto E detaching from C
+saving bundle to 
+adding branch
+adding changesets
+adding manifests
+adding file changes
+added 2 changesets with 2 changes to 2 files (+1 heads)
+rebase completed
+@  4: D
+|
+o  3: E
+|
+| o  2: C
+| |
+| o  1: B
+|/
+o  0: A
+
+Expected A, D, E
+A
+D
+E
+
+@  4: E
+|
+| o  3: D
+| |
+| o  2: C
+| |
+| o  1: B
+|/
+o  0: A
+
+% Rebasing C onto E detaching from B
+saving bundle to 
+adding branch
+adding changesets
+adding manifests
+adding file changes
+added 3 changesets with 3 changes to 3 files (+1 heads)
+rebase completed
+@  4: D
+|
+o  3: C
+|
+o  2: E
+|
+| o  1: B
+|/
+o  0: A
+
+Expected A, C, D, E
+A
+C
+D
+E
+
+@  4: E
+|
+| o  3: D
+| |
+| o  2: C
+| |
+| o  1: B
+|/
+o  0: A
+
+% Rebasing B onto E using detach (same as not using it)
+saving bundle to 
+adding branch
+adding changesets
+adding manifests
+adding file changes
+added 4 changesets with 4 changes to 4 files
+rebase completed
+@  4: D
+|
+o  3: C
+|
+o  2: B
+|
+o  1: E
+|
+o  0: A
+
+Expected A, B, C, D, E
+A
+B
+C
+D
+E
+
+@  4: E
+|
+| o  3: D
+| |
+| o  2: C
+| |
+| o  1: B
+|/
+o  0: A
+
+% Rebasing C onto E detaching from B and collapsing
+saving bundle to 
+adding branch
+adding changesets
+adding manifests
+adding file changes
+added 2 changesets with 3 changes to 3 files (+1 heads)
+rebase completed
+@  3: Collapsed revision
+|  * C
+|  * D
+o  2: E
+|
+| o  1: B
+|/
+o  0: A
+
+Expected A, C, D, E
+A
+C
+D
+E
diff --git a/tests/test-rebase-parameters.out b/tests/test-rebase-parameters.out
--- a/tests/test-rebase-parameters.out
+++ b/tests/test-rebase-parameters.out
@@ -2,7 +2,7 @@
 
 % Use continue and abort
 hg rebase: cannot use both abort and continue
-hg rebase [-s REV | -b REV] [-d REV] [--collapse] [--keep] [--keepbranches] | [-c] | [-a]
+hg rebase [-s REV | -b REV] [-d REV] [--collapse] [--detach] [--keep] [--keepbranches] | [-c] | [-a]
 
 move changeset (and descendants) to a different branch
 
@@ -21,6 +21,7 @@ options:
     --collapse      collapse the rebased changesets
     --keep          keep original changesets
     --keepbranches  keep original branch names
+    --detach        force detaching of source from its original branch
  -c --continue      continue an interrupted rebase
  -a --abort         abort an interrupted rebase
     --style         display using template map file
@@ -30,7 +31,7 @@ use "hg -v help rebase" to show global o
 
 % Use continue and collapse
 hg rebase: cannot use collapse with continue or abort
-hg rebase [-s REV | -b REV] [-d REV] [--collapse] [--keep] [--keepbranches] | [-c] | [-a]
+hg rebase [-s REV | -b REV] [-d REV] [--collapse] [--detach] [--keep] [--keepbranches] | [-c] | [-a]
 
 move changeset (and descendants) to a different branch
 
@@ -49,6 +50,7 @@ options:
     --collapse      collapse the rebased changesets
     --keep          keep original changesets
     --keepbranches  keep original branch names
+    --detach        force detaching of source from its original branch
  -c --continue      continue an interrupted rebase
  -a --abort         abort an interrupted rebase
     --style         display using template map file
@@ -58,7 +60,7 @@ use "hg -v help rebase" to show global o
 
 % Use continue/abort and dest/source
 hg rebase: abort and continue do not allow specifying revisions
-hg rebase [-s REV | -b REV] [-d REV] [--collapse] [--keep] [--keepbranches] | [-c] | [-a]
+hg rebase [-s REV | -b REV] [-d REV] [--collapse] [--detach] [--keep] [--keepbranches] | [-c] | [-a]
 
 move changeset (and descendants) to a different branch
 
@@ -77,6 +79,7 @@ options:
     --collapse      collapse the rebased changesets
     --keep          keep original changesets
     --keepbranches  keep original branch names
+    --detach        force detaching of source from its original branch
  -c --continue      continue an interrupted rebase
  -a --abort         abort an interrupted rebase
     --style         display using template map file
@@ -86,7 +89,7 @@ use "hg -v help rebase" to show global o
 
 % Use source and base
 hg rebase: cannot specify both a revision and a base
-hg rebase [-s REV | -b REV] [-d REV] [--collapse] [--keep] [--keepbranches] | [-c] | [-a]
+hg rebase [-s REV | -b REV] [-d REV] [--collapse] [--detach] [--keep] [--keepbranches] | [-c] | [-a]
 
 move changeset (and descendants) to a different branch
 
@@ -105,6 +108,7 @@ options:
     --collapse      collapse the rebased changesets
     --keep          keep original changesets
     --keepbranches  keep original branch names
+    --detach        force detaching of source from its original branch
  -c --continue      continue an interrupted rebase
  -a --abort         abort an interrupted rebase
     --style         display using template map file