diff --git a/nvmet/nvme.py b/nvmet/nvme.py
index c3cfa746c082c0f69cc8c2a07bd202c5ed2251e8..c1820400cf50d6b28ce8ee40794b5ad5bdcfe73a 100644
--- a/nvmet/nvme.py
+++ b/nvmet/nvme.py
@@ -436,11 +436,11 @@ class Namespace(CFSNode):
                     nsid = index
                     break
             if nsid is None:
-                raise CFSError("All NSIDs 0-%d in use" % self.MAX_NSID)
+                raise CFSError("All NSIDs 1-%d in use" % self.MAX_NSID)
         else:
             nsid = int(nsid)
-            if nsid < 0 or nsid > self.MAX_NSID:
-                raise CFSError("NSID must be 0 to %d" % self.MAX_NSID)
+            if nsid < 1 or nsid > self.MAX_NSID:
+                raise CFSError("NSID must be 1 to %d" % self.MAX_NSID)
 
         self._attr_groups = ['device']
         self._subsystem = subsystem