diff --git a/x/staking/simulation/operations.go b/x/staking/simulation/operations.go
index bf2919257840..5be48161ca8f 100644
--- a/x/staking/simulation/operations.go
+++ b/x/staking/simulation/operations.go
@@ -832,6 +832,17 @@ func SimulateMsgRotateConsPubKey(txGen client.TxConfig, ak types.AccountKeeper,
 			return simtypes.NoOpMsg(types.ModuleName, msgType, "unable to build msg"), nil, err
 		}
 
+		// check if there's another key rotation for this same key in the same block
+		allRotations, err := k.GetBlockConsPubKeyRotationHistory(ctx)
+		if err != nil {
+			return simtypes.NoOpMsg(types.ModuleName, msgType, "cannot get block cons key rotation history"), nil, err
+		}
+		for _, r := range allRotations {
+			if r.NewConsPubkey.Compare(msg.NewPubkey) == 0 {
+				return simtypes.NoOpMsg(types.ModuleName, msgType, "cons key already used in this block"), nil, nil
+			}
+		}
+
 		txCtx := simulation.OperationInput{
 			R:               r,
 			App:             app,