diff --git a/mpcdf_common.py b/mpcdf_common.py
index 065f615ba9b09a19e45a1fe5f1f9fe7450af86ca..66243e885f8df1a5fe1eea4bfb906536abd5df85 100644
--- a/mpcdf_common.py
+++ b/mpcdf_common.py
@@ -147,7 +147,7 @@ def mpcdf_enable_repositories(api_url, project, package, verbose=False):
     return True
 
 
-def mpcdf_setup_repos(api_url, project, distribution, parent=None, packages=None, dry_run=False):
+def mpcdf_setup_repos(api_url, project, distribution=None, parent=None, packages=None, dry_run=False):
     if parent:
         for attribute in ["MPCDF:compiler_modules", "MPCDF:mpi_modules", "MPCDF:cuda_modules"]:
             try:
@@ -160,6 +160,12 @@ def mpcdf_setup_repos(api_url, project, distribution, parent=None, packages=None
     mpis = list(get_attribute_values(api_url, project, None, "MPCDF:mpi_modules"))
     cudas = list(get_attribute_values(api_url, project, None, "MPCDF:cuda_modules"))
 
+    if distribution is None:
+        # Get existing value from project meta
+        distribution = project_meta(api_url, project if parent is None else parent).find(
+            "./repository[@name='System']/path[@project='distributions']").get("repository")
+        print("Using '{0}' as base distribution".format(distribution))
+
     distributions = project_meta(api_url, "distributions")
     dist_repo = distributions.find('./repository[@name="{0}"]'.format(distribution))
     if dist_repo is None:
diff --git a/mpcdf_setup_repos.py b/mpcdf_setup_repos.py
index e8169697602a283c6493af586486a53dbc86d0ad..490bb18e861ea8173d7e6291e2530ce549a2c9b2 100644
--- a/mpcdf_setup_repos.py
+++ b/mpcdf_setup_repos.py
@@ -9,16 +9,12 @@ import osc.conf
 import osc.core
 import osc.cmdln
 
-default_distribution = "SLE_12_SP1"
-
-
 @osc.cmdln.option('-n', '--dry-run', action="store_true",
                   help="Do not actually run anything but output the resulting XML configuration")
 @osc.cmdln.option('--parent', metavar="PARENT",
                   help="Setup the repositories to be based on the upstream project PARENT (e.g. for home: projects)")
 @osc.cmdln.option('--distribution',
-                  default=default_distribution,
-                  help="Base distribution [default: %default]")
+                  help="Base distribution, necessary argument unless set previously for this project")
 def do_mpcdf_setup_repos(self, subcmd, opts, *args):
     """${cmd_name}: Create all repository combinations for an MPCDF project