diff --git a/manticore/__main__.py b/manticore/__main__.py
index a7459e2..d32a249 100644
--- a/manticore/__main__.py
+++ b/manticore/__main__.py
@@ -40,7 +40,7 @@ def parse_arguments():
     parser.add_argument('--dumpafter', type=int, default=0, help='Dump state after every N instructions; 0 to disable')
     parser.add_argument('--maxstorage', type=int, default=0, help='Storage use cap in megabytes.')
     parser.add_argument('--maxstates', type=int, default=0, help='Maximun number of states to mantain at the same time')
-    parser.add_argument('--procs', type=int, default=1, choices=xrange(1, 20), help='Number of parallel workers to spawn')
+    parser.add_argument('--procs', type=int, default=1, help='Number of parallel workers to spawn')
     parser.add_argument('--timeout', type=int, default=0, help='Timeout. Abort exploration aftr TIMEOUT seconds')
     parser.add_argument('--replay', type=str, default=None,
                        help='The trace filename to replay')