diff --git a/mercurial/exchange.py b/mercurial/exchange.py
--- a/mercurial/exchange.py
+++ b/mercurial/exchange.py
@@ -944,8 +944,22 @@ def _pullbundle2(pullop):
         raise util.Abort('missing support for %s' % exc)
 
     if pullop.fetch:
-        assert len(op.records['changegroup']) == 1
-        pullop.cgresult = op.records['changegroup'][0]['return']
+        changedheads = 0
+        pullop.cgresult = 1
+        for cg in op.records['changegroup']:
+            ret = cg['return']
+            # If any changegroup result is 0, return 0
+            if ret == 0:
+                pullop.cgresult = 0
+                break
+            if ret < -1:
+                changedheads += ret + 1
+            elif ret > 1:
+                changedheads += ret - 1
+        if changedheads > 0:
+            pullop.cgresult = 1 + changedheads
+        elif changedheads < 0:
+            pullop.cgresult = -1 + changedheads
 
     # processing phases change
     for namespace, value in op.records['listkeys']:
diff --git a/tests/test-bundle2-multiple-changegroups.t b/tests/test-bundle2-multiple-changegroups.t
new file mode 100644
--- /dev/null
+++ b/tests/test-bundle2-multiple-changegroups.t
@@ -0,0 +1,261 @@
+Create an extension to test bundle2 with multiple changegroups
+
+  $ cat > bundle2.py <<EOF
+  > """
+  > """
+  > from mercurial import changegroup, exchange
+  > 
+  > def _getbundlechangegrouppart(bundler, repo, source, bundlecaps=None,
+  >                               b2caps=None, heads=None, common=None,
+  >                               **kwargs):
+  >     # Create two changegroups given the common changesets and heads for the
+  >     # changegroup part we are being requested. Use the parent of each head
+  >     # in 'heads' as intermediate heads for the first changegroup.
+  >     intermediates = [repo[r].p1().node() for r in heads]
+  >     cg = changegroup.getchangegroup(repo, source, heads=intermediates,
+  >                                      common=common, bundlecaps=bundlecaps)
+  >     bundler.newpart('b2x:output', data='changegroup1')
+  >     bundler.newpart('b2x:changegroup', data=cg.getchunks())
+  >     cg = changegroup.getchangegroup(repo, source, heads=heads,
+  >                                      common=common + intermediates,
+  >                                      bundlecaps=bundlecaps)
+  >     bundler.newpart('b2x:output', data='changegroup2')
+  >     bundler.newpart('b2x:changegroup', data=cg.getchunks())
+  > 
+  > def _pull(repo, *args, **kwargs):
+  >   pullop = _orig_pull(repo, *args, **kwargs)
+  >   repo.ui.write('pullop.cgresult is %d\n' % pullop.cgresult)
+  >   return pullop
+  > 
+  > _orig_pull = exchange.pull
+  > exchange.pull = _pull
+  > exchange.getbundle2partsmapping['changegroup'] = _getbundlechangegrouppart
+  > EOF
+
+  $ cat >> $HGRCPATH << EOF
+  > [experimental]
+  > bundle2-exp=True
+  > [ui]
+  > logtemplate={rev}:{node|short} {phase} {author} {bookmarks} {desc|firstline}
+  > EOF
+
+Start with a simple repository with a single commit
+
+  $ hg init repo
+  $ cd repo
+  $ cat > .hg/hgrc << EOF
+  > [extensions]
+  > bundle2=$TESTTMP/bundle2.py
+  > EOF
+
+  $ echo A > A
+  $ hg commit -A -m A -q
+  $ cd ..
+
+Clone
+
+  $ hg clone -q repo clone
+
+Add two linear commits
+
+  $ cd repo
+  $ echo B > B
+  $ hg commit -A -m B -q
+  $ echo C > C
+  $ hg commit -A -m C -q
+
+  $ cd ../clone
+  $ cat >> .hg/hgrc <<EOF
+  > [hooks]
+  > pretxnchangegroup = sh -c "python \"$TESTDIR/printenv.py\" pretxnchangegroup"
+  > changegroup = sh -c "python \"$TESTDIR/printenv.py\" changegroup"
+  > incoming = sh -c "python \"$TESTDIR/printenv.py\" incoming"
+  > EOF
+
+Pull the new commits in the clone
+
+  $ hg pull
+  pulling from $TESTTMP/repo (glob)
+  searching for changes
+  remote: changegroup1
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files
+  pretxnchangegroup hook: HG_NODE=27547f69f25460a52fff66ad004e58da7ad3fb56 HG_PENDING=$TESTTMP/clone HG_SOURCE=bundle2 HG_URL=bundle2
+  remote: changegroup2
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files
+  pretxnchangegroup hook: HG_NODE=f838bfaca5c7226600ebcfd84f3c3c13a28d3757 HG_PENDING=$TESTTMP/clone HG_PHASES_MOVED=1 HG_SOURCE=bundle2 HG_URL=bundle2
+  changegroup hook: HG_NODE=27547f69f25460a52fff66ad004e58da7ad3fb56 HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=27547f69f25460a52fff66ad004e58da7ad3fb56 HG_SOURCE=bundle2 HG_URL=bundle2
+  changegroup hook: HG_NODE=f838bfaca5c7226600ebcfd84f3c3c13a28d3757 HG_PHASES_MOVED=1 HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=f838bfaca5c7226600ebcfd84f3c3c13a28d3757 HG_SOURCE=bundle2 HG_URL=bundle2
+  pullop.cgresult is 1
+  (run 'hg update' to get a working copy)
+  $ hg update
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg log -G
+  @  2:f838bfaca5c7 public test  C
+  |
+  o  1:27547f69f254 public test  B
+  |
+  o  0:4a2df7238c3b public test  A
+  
+Add more changesets with multiple heads to the original repository
+
+  $ cd ../repo
+  $ echo D > D
+  $ hg commit -A -m D -q
+  $ hg up -r 1
+  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
+  $ echo E > E
+  $ hg commit -A -m E -q
+  $ echo F > F
+  $ hg commit -A -m F -q
+  $ hg up -r 1
+  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
+  $ echo G > G
+  $ hg commit -A -m G -q
+  $ hg up -r 3
+  2 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ echo H > H
+  $ hg commit -A -m H -q
+  $ hg log -G
+  @  7:5cd59d311f65 draft test  H
+  |
+  | o  6:1d14c3ce6ac0 draft test  G
+  | |
+  | | o  5:7f219660301f draft test  F
+  | | |
+  | | o  4:8a5212ebc852 draft test  E
+  | |/
+  o |  3:b3325c91a4d9 draft test  D
+  | |
+  o |  2:f838bfaca5c7 draft test  C
+  |/
+  o  1:27547f69f254 draft test  B
+  |
+  o  0:4a2df7238c3b draft test  A
+  
+New heads are reported during transfer and properly accounted for in
+pullop.cgresult
+
+  $ cd ../clone
+  $ hg pull
+  pulling from $TESTTMP/repo (glob)
+  searching for changes
+  remote: changegroup1
+  adding changesets
+  adding manifests
+  adding file changes
+  added 2 changesets with 2 changes to 2 files (+1 heads)
+  pretxnchangegroup hook: HG_NODE=b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e HG_PENDING=$TESTTMP/clone HG_SOURCE=bundle2 HG_URL=bundle2
+  remote: changegroup2
+  adding changesets
+  adding manifests
+  adding file changes
+  added 3 changesets with 3 changes to 3 files (+1 heads)
+  pretxnchangegroup hook: HG_NODE=7f219660301fe4c8a116f714df5e769695cc2b46 HG_PENDING=$TESTTMP/clone HG_PHASES_MOVED=1 HG_SOURCE=bundle2 HG_URL=bundle2
+  changegroup hook: HG_NODE=b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=b3325c91a4d916bcc4cdc83ea3fe4ece46a42f6e HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=8a5212ebc8527f9fb821601504794e3eb11a1ed3 HG_SOURCE=bundle2 HG_URL=bundle2
+  changegroup hook: HG_NODE=7f219660301fe4c8a116f714df5e769695cc2b46 HG_PHASES_MOVED=1 HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=7f219660301fe4c8a116f714df5e769695cc2b46 HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=1d14c3ce6ac0582d2809220d33e8cd7a696e0156 HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=5cd59d311f6508b8e0ed28a266756c859419c9f1 HG_SOURCE=bundle2 HG_URL=bundle2
+  pullop.cgresult is 3
+  (run 'hg heads' to see heads, 'hg merge' to merge)
+  $ hg log -G
+  o  7:5cd59d311f65 public test  H
+  |
+  | o  6:1d14c3ce6ac0 public test  G
+  | |
+  | | o  5:7f219660301f public test  F
+  | | |
+  | | o  4:8a5212ebc852 public test  E
+  | |/
+  o |  3:b3325c91a4d9 public test  D
+  | |
+  @ |  2:f838bfaca5c7 public test  C
+  |/
+  o  1:27547f69f254 public test  B
+  |
+  o  0:4a2df7238c3b public test  A
+  
+Removing a head from the original repository by merging it
+
+  $ cd ../repo
+  $ hg merge -r 6 -q
+  $ hg commit -m Merge
+  $ echo I > I
+  $ hg commit -A -m H -q
+  $ hg log -G
+  @  9:9d18e5bd9ab0 draft test  H
+  |
+  o    8:71bd7b46de72 draft test  Merge
+  |\
+  | o  7:5cd59d311f65 draft test  H
+  | |
+  o |  6:1d14c3ce6ac0 draft test  G
+  | |
+  | | o  5:7f219660301f draft test  F
+  | | |
+  +---o  4:8a5212ebc852 draft test  E
+  | |
+  | o  3:b3325c91a4d9 draft test  D
+  | |
+  | o  2:f838bfaca5c7 draft test  C
+  |/
+  o  1:27547f69f254 draft test  B
+  |
+  o  0:4a2df7238c3b draft test  A
+  
+Removed heads are reported during transfer and properly accounted for in
+pullop.cgresult
+
+  $ cd ../clone
+  $ hg pull
+  pulling from $TESTTMP/repo (glob)
+  searching for changes
+  remote: changegroup1
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 0 changes to 0 files (-1 heads)
+  pretxnchangegroup hook: HG_NODE=71bd7b46de72e69a32455bf88d04757d542e6cf4 HG_PENDING=$TESTTMP/clone HG_SOURCE=bundle2 HG_URL=bundle2
+  remote: changegroup2
+  adding changesets
+  adding manifests
+  adding file changes
+  added 1 changesets with 1 changes to 1 files
+  pretxnchangegroup hook: HG_NODE=9d18e5bd9ab09337802595d49f1dad0c98df4d84 HG_PENDING=$TESTTMP/clone HG_PHASES_MOVED=1 HG_SOURCE=bundle2 HG_URL=bundle2
+  changegroup hook: HG_NODE=71bd7b46de72e69a32455bf88d04757d542e6cf4 HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=71bd7b46de72e69a32455bf88d04757d542e6cf4 HG_SOURCE=bundle2 HG_URL=bundle2
+  changegroup hook: HG_NODE=9d18e5bd9ab09337802595d49f1dad0c98df4d84 HG_PHASES_MOVED=1 HG_SOURCE=bundle2 HG_URL=bundle2
+  incoming hook: HG_NODE=9d18e5bd9ab09337802595d49f1dad0c98df4d84 HG_SOURCE=bundle2 HG_URL=bundle2
+  pullop.cgresult is -2
+  (run 'hg update' to get a working copy)
+  $ hg log -G
+  o  9:9d18e5bd9ab0 public test  H
+  |
+  o    8:71bd7b46de72 public test  Merge
+  |\
+  | o  7:5cd59d311f65 public test  H
+  | |
+  o |  6:1d14c3ce6ac0 public test  G
+  | |
+  | | o  5:7f219660301f public test  F
+  | | |
+  +---o  4:8a5212ebc852 public test  E
+  | |
+  | o  3:b3325c91a4d9 public test  D
+  | |
+  | @  2:f838bfaca5c7 public test  C
+  |/
+  o  1:27547f69f254 public test  B
+  |
+  o  0:4a2df7238c3b public test  A
+