diff --git a/lib/modules/deployment/contract_deployer.js b/lib/modules/deployment/contract_deployer.js
index e57dbefb..531b0be6 100644
--- a/lib/modules/deployment/contract_deployer.js
+++ b/lib/modules/deployment/contract_deployer.js
@@ -275,7 +275,7 @@ class ContractDeployer {
           if (error) {
             contract.error = error.message;
             self.events.emit("deploy:contract:error", contract);
-            if (error.message && error.message.indexOf('replacement transaction underpriced')) {
+            if (error.message && error.message.indexOf('replacement transaction underpriced') !== -1) {
               self.logger.warn("replacement transaction underpriced: This warning typically means a transaction exactly like this one is still pending on the blockchain");
             }
             return next(new Error("error deploying =" + contract.className + "= due to error: " + error.message));