diff --git a/lib/client.js b/lib/client.js
index 89fd40d1..cfdac52d 100644
--- a/lib/client.js
+++ b/lib/client.js
@@ -620,7 +620,7 @@ class Client extends EventEmitter {
       maxApdu: options.maxApdu || baEnum.MaxApduLengthAccepted.OCTETS_1476,
       invokeId: options.invokeId || this._getInvokeId(),
       arrayIndex: options.arrayIndex || baEnum.ASN1_ARRAY_ALL,
-      priority: options.priority
+      priority: options.priority || baEnum.ASN1_NO_PRIORITY
     };
     const buffer = this._getBuffer();
     baNpdu.encode(buffer, baEnum.NpduControlPriority.NORMAL_MESSAGE | baEnum.NpduControlBits.EXPECTING_REPLY, address, null, DEFAULT_HOP_COUNT, baEnum.NetworkLayerMessageType.WHO_IS_ROUTER_TO_NETWORK, 0);