diff --git a/lib/contracts/code_generator.js b/lib/contracts/code_generator.js
index 2a4e80190..54b550a16 100644
--- a/lib/contracts/code_generator.js
+++ b/lib/contracts/code_generator.js
@@ -101,9 +101,11 @@ class CodeGenerator {
       self.buildWeb3JS(cb);
     });
 
-    this.events.setCommandHandler('code-generator:contract', (contractName, cb) => {
-      let contract = self.contractsManager.contracts[contractName];
-      self.buildContractJS(contractName, self.generateContractJSON(contractName, contract), cb);
+    this.events.removeListener('code-generator:contract', () => {
+      self.events.setCommandHandler('code-generator:contract', (contractName, cb) => {
+        let contract = self.contractsManager.contracts[contractName];
+        self.buildContractJS(contractName, self.generateContractJSON(contractName, contract), cb);
+      });
     });
 
   }
diff --git a/lib/contracts/contracts.js b/lib/contracts/contracts.js
index 81b5ed37b..e76bdef86 100644
--- a/lib/contracts/contracts.js
+++ b/lib/contracts/contracts.js
@@ -27,8 +27,10 @@ class ContractsManager {
     });
 
     const self = this;
-    this.events.setCommandHandler('contracts:list', (cb) => {
-      cb(self.listContracts());
+    this.events.removeListener('contracts:list', () => {
+      self.events.setCommandHandler('contracts:list', (cb) => {
+        cb(self.listContracts());
+      });
     });
   }