diff --git a/ib_insync/ib.py b/ib_insync/ib.py
index dbe53cde..96012bca 100644
--- a/ib_insync/ib.py
+++ b/ib_insync/ib.py
@@ -1333,6 +1333,8 @@ def reqMktDepth(
         """
         reqId = self.client.getReqId()
         ticker = self.wrapper.startTicker(reqId, contract, 'mktDepth')
+        ticker.domBids.clear()
+        ticker.domAsks.clear()
         self.client.reqMktDepth(
             reqId, contract, numRows, isSmartDepth, mktDepthOptions)
         return ticker
@@ -1349,8 +1351,6 @@ def cancelMktDepth(self, contract: Contract, isSmartDepth=False):
         reqId = self.wrapper.endTicker(ticker, 'mktDepth') if ticker else 0
         if ticker and reqId:
             self.client.cancelMktDepth(reqId, isSmartDepth)
-            ticker.domBids.clear()
-            ticker.domAsks.clear()
         else:
             self._logger.error(
                 f'cancelMktDepth: No reqId found for contract {contract}')