diff --git a/remix-simulator/src/methods/accounts.js b/remix-simulator/src/methods/accounts.js
index b0563c7c57..176cd129c4 100644
--- a/remix-simulator/src/methods/accounts.js
+++ b/remix-simulator/src/methods/accounts.js
@@ -45,7 +45,7 @@ Accounts.prototype.methods = function () {
 }
 
 Accounts.prototype.eth_accounts = function (payload, cb) {
-  return cb(null, this.accountsList.map((x) => x.address))
+  return cb(null, this.accountsList.map((x) => ethJSUtil.toChecksumAddress(x.address)))
 }
 
 Accounts.prototype.eth_getBalance = function (payload, cb) {
diff --git a/remix-simulator/src/methods/transactions.js b/remix-simulator/src/methods/transactions.js
index 75e82a20d1..b861fc4b3d 100644
--- a/remix-simulator/src/methods/transactions.js
+++ b/remix-simulator/src/methods/transactions.js
@@ -26,6 +26,10 @@ Transactions.prototype.methods = function () {
 }
 
 Transactions.prototype.eth_sendTransaction = function (payload, cb) {
+  // from might be lowercased address (web3)
+  if (payload.params && payload.params.length > 0 && payload.params[0].from) {
+    payload.params[0].from = ethJSUtil.toChecksumAddress(payload.params[0].from)
+  }
   processTx(this.accounts, payload, false, cb)
 }
 
@@ -70,6 +74,10 @@ Transactions.prototype.eth_getCode = function (payload, cb) {
 }
 
 Transactions.prototype.eth_call = function (payload, cb) {
+  // from might be lowercased address (web3)
+  if (payload.params && payload.params.length > 0 && payload.params[0].from) {
+    payload.params[0].from = ethJSUtil.toChecksumAddress(payload.params[0].from)
+  }
   processTx(this.accounts, payload, true, cb)
 }