diff --git a/osc/build.py b/osc/build.py
index 05beb530..50aa8c85 100644
--- a/osc/build.py
+++ b/osc/build.py
@@ -765,8 +765,9 @@ def main(apiurl, opts, argv):
                       enable_cpio = not opts.disable_cpio_bulk_download,
                       cookiejar=cookiejar)
 
-    # implicitly trust the project we are building for
-    check_trusted_projects(apiurl, [ i for i in bi.projects.keys() if not i == prj ])
+    if not opts.trust_all_projects:
+        # implicitly trust the project we are building for
+        check_trusted_projects(apiurl, [ i for i in bi.projects.keys() if not i == prj ])
 
     # now update the package cache
     fetcher.run(bi)
diff --git a/osc/commandline.py b/osc/commandline.py
index 33e1a6a4..ff355b32 100644
--- a/osc/commandline.py
+++ b/osc/commandline.py
@@ -5579,6 +5579,8 @@ Please submit there instead, or use --nodevelproject to force direct submission.
                   help=SUPPRESS_HELP)
     @cmdln.option('--host', metavar='HOST',
             help='perform the build on a remote server - user@server:~/remote/directory')
+    @cmdln.option('--trust-all-projects', action='store_true',
+                  help='trust packages from all projects')
     def do_build(self, subcmd, opts, *args):
         """${cmd_name}: Build a package on your local machine