diff --git a/Vagrantfile b/Vagrantfile
index 661dc0f5..a1dbb7f6 100644
--- a/Vagrantfile
+++ b/Vagrantfile
@@ -15,6 +15,7 @@ $script = <<SCRIPT
         koji \
         krb5-workstation \
         libffi-devel \
+        mock-scm \
         openssl-devel \
         python \
         python-devel \
diff --git a/module_build_service/builder/MockModuleBuilder.py b/module_build_service/builder/MockModuleBuilder.py
index 4e8366b0..8f2461df 100644
--- a/module_build_service/builder/MockModuleBuilder.py
+++ b/module_build_service/builder/MockModuleBuilder.py
@@ -43,6 +43,7 @@ from utils import (
     create_local_repo_from_koji_tag,
     execute_cmd,
     find_srpm,
+    get_koji_config
 )
 from KojiModuleBuilder import KojiModuleBuilder
 from module_build_service.models import ModuleBuild
@@ -308,12 +309,20 @@ class MockModuleBuilder(GenericBuilder):
                 if repo_name.startswith("module-"):
                     repo_name = repo_name[7:]
                 repo_dir = tag
+                baseurl = "file://" + repo_dir
             else:
                 repo_name = tag
-                repo_dir = os.path.join(self.config.cache_dir, "koji_tags", tag)
-                create_local_repo_from_koji_tag(self.config, tag, repo_dir,
-                                                [self.arch, "noarch"])
-            baseurl = "file://" + repo_dir
+                koji_config = get_koji_config(self.config)
+                koji_session = koji.ClientSession(koji_config.server, opts=koji_config)
+                repo = koji_session.getRepo(repo_name)
+                if repo:
+                    baseurl = koji.PathInfo(topdir=koji_config.topurl).repo(repo['id'], repo_name)
+                    baseurl = '{0}/{1}/'.format(baseurl, self.arch)
+                else:
+                    repo_dir = os.path.join(self.config.cache_dir, "koji_tags", tag)
+                    create_local_repo_from_koji_tag(self.config, tag, repo_dir,
+                                                    [self.arch, "noarch"])
+                    baseurl = "file://" + repo_dir
             self._add_repo(repo_name, baseurl)
         self._write_mock_config()
 
diff --git a/module_build_service/builder/utils.py b/module_build_service/builder/utils.py
index a1e29a53..aa616f69 100644
--- a/module_build_service/builder/utils.py
+++ b/module_build_service/builder/utils.py
@@ -49,6 +49,24 @@ def execute_cmd(args, stdout=None, stderr=None, cwd=None):
     return out, err
 
 
+def get_koji_config(mbs_config):
+    """
+    Get the Koji config needed for MBS
+    :param mbs_config: an MBS config object
+    :return: a Munch object of the Koji config
+    """
+    # Placed here to avoid py2/py3 conflicts...
+    import koji
+
+    koji_config = munch.Munch(koji.read_config(
+        profile_name=mbs_config.koji_profile,
+        user_config=mbs_config.koji_config,
+    ))
+    # Timeout after 10 minutes.  The default is 12 hours.
+    koji_config["timeout"] = 60 * 10
+    return koji_config
+
+
 def create_local_repo_from_koji_tag(config, tag, repo_dir, archs=None):
     """
     Downloads the packages build for one of `archs` (defaults to ['x86_64',
@@ -63,13 +81,7 @@ def create_local_repo_from_koji_tag(config, tag, repo_dir, archs=None):
         archs = ["x86_64", "noarch"]
 
     # Load koji config and create Koji session.
-    koji_config = munch.Munch(koji.read_config(
-        profile_name=config.koji_profile,
-        user_config=config.koji_config,
-    ))
-    # Timeout after 10 minutes.  The default is 12 hours.
-    koji_config["timeout"] = 60 * 10
-
+    koji_config = get_koji_config(config)
     address = koji_config.server
     log.info("Connecting to koji %r" % address)
     session = koji.ClientSession(address, opts=koji_config)