diff --git a/src/mongo/db/catalog/index_catalog.cpp b/src/mongo/db/catalog/index_catalog.cpp
index af5babf..7db1014 100644
--- a/src/mongo/db/catalog/index_catalog.cpp
+++ b/src/mongo/db/catalog/index_catalog.cpp
@@ -463,6 +463,19 @@ namespace mongo {
 
         }
 
+        BSONObjIterator i(key);
+        while (i.more()) {
+            BSONElement e = i.next();
+            if (e.isNumber()) {
+                double dval = e.number();
+                if (dval != 1 && dval != -1) {
+                    string s = str::stream() << "Must specify ascending/descending with 1 and -1, "
+                                             << "but found: " << e;
+                    return Status( ErrorCodes::CannotCreateIndex, s );
+                }
+            }
+        }
+
         return Status::OK();
     }