diff --git a/module_build_service/utils/reuse.py b/module_build_service/utils/reuse.py

index efbbc0a..dcdbc07 100644

--- a/module_build_service/utils/reuse.py

+++ b/module_build_service/utils/reuse.py

@@ -25,7 +25,7 @@

 import kobo.rpmlib

 import module_build_service.messaging

-from module_build_service import log, models, conf

+from module_build_service import log, models, conf, glib

 def reuse_component(component, previous_component_build,

@@ -110,6 +110,27 @@ def _get_reusable_module(session, module):

         log.info("Cannot re-use.  %r is the first module build." % module)

         return None

+    xmd = glib.from_variant_dict(mmd.get_xmd())

+    old_mmd = previous_module_build.mmd()

+    old_xmd = glib.from_variant_dict(old_mmd.get_xmd())

+

+    try:

+        # Make sure that the module buildrequires commit hashes are exactly the same

+        for br_module_name, br_module in xmd['mbs']['buildrequires'].items():

+            # Assumes that the streams have been replaced with commit hashes, so we

+            # can compare to see if they have changed. Since a build is unique to

+            # a commit hash, this is a safe test.

+            ref1 = br_module.get('ref')

+            ref2 = old_xmd['mbs']['buildrequires'][br_module_name].get('ref')

+            if not (ref1 and ref2) or ref1 != ref2:

+                log.info('Cannot re-use.  The buildrequired module %s ref hash changed',

+                         br_module_name)

+                return None

+    except KeyError:

+        log.info('Cannot re-use.  The buildrequired module %s does not have the same '

+                 'set of buildrequires.', br_module_name)

+        return None

+

     return previous_module_build