diff --git a/src/TxBrowser.js b/src/TxBrowser.js
index 1c4abdf5a5..d950428c7e 100644
--- a/src/TxBrowser.js
+++ b/src/TxBrowser.js
@@ -10,7 +10,7 @@ function TxBrowser (_web3) {
   this.web3 = _web3
 
   this.blockNumber
-  this.txNumber = '0x20ef65b8b186ca942fcccd634f37074dde49b541c27994fc7596740ef44cfd51'
+  this.txNumber = '0x71a6d583d16d142c5c3e8903060e8a4ee5a5016348a9448df6c3e63b68076ec4'
   this.hash
   this.from
   this.to
diff --git a/src/trace/traceAnalyser.js b/src/trace/traceAnalyser.js
index b482ae86d3..897bd6b8a4 100644
--- a/src/trace/traceAnalyser.js
+++ b/src/trace/traceAnalyser.js
@@ -21,20 +21,40 @@ TraceAnalyser.prototype.analyse = function (trace, tx, callback) {
   if (traceHelper.isContractCreation(tx.to)) {
     this.traceCache.pushContractCreation(tx.to, tx.input)
   }
+  this.buildCalldata(0, this.trace[0], tx, true)
 
   for (var k = 0; k < this.trace.length; k++) {
     var step = this.trace[k]
-    this.buildCalldata(k, step)
     this.buildMemory(k, step)
-    this.buildDepth(k, step, callStack)
+    this.buildDepth(k, step, tx, callStack)
     context = this.buildStorage(k, step, context)
   }
   callback(null, true)
 }
 
-TraceAnalyser.prototype.buildCalldata = function (index, step) {
-  if (step.calldata) {
-    this.traceCache.pushCallDataChanges(index)
+TraceAnalyser.prototype.buildCalldata = function (index, step, tx, newContext) {
+  var calldata = ''
+  if (index === 0) {
+    calldata = tx.input
+    this.traceCache.pushCallDataChanges(index, calldata)
+  } else if (!newContext) {
+    var lastCall = this.traceCache.callsData[this.traceCache.callDataChanges[this.traceCache.callDataChanges.length - 2]]
+    this.traceCache.pushCallDataChanges(index + 1, lastCall)
+  } else {
+    var memory = this.trace[this.traceCache.memoryChanges[this.traceCache.memoryChanges.length - 1]].memory
+    var callStep = this.trace[index]
+    var stack = callStep.stack
+    var offset = ''
+    var size = ''
+    if (callStep.op === 'DELEGATECALL') {
+      offset = 2 * parseInt(stack[stack.length - 3], 16)
+      size = 2 * parseInt(stack[stack.length - 4], 16)
+    } else {
+      offset = 2 * parseInt(stack[stack.length - 4], 16)
+      size = 2 * parseInt(stack[stack.length - 5], 16)
+    }
+    calldata = '0x' + memory.join('').substr(offset, size)
+    this.traceCache.pushCallDataChanges(index + 1, calldata)
   }
 }
 
@@ -62,7 +82,7 @@ TraceAnalyser.prototype.buildStorage = function (index, step, context) {
   return context
 }
 
-TraceAnalyser.prototype.buildDepth = function (index, step, callStack) {
+TraceAnalyser.prototype.buildDepth = function (index, step, tx, callStack) {
   if (traceHelper.isCallInstruction(step) && !traceHelper.isCallToPrecompiledContract(index, this.trace)) {
     if (traceHelper.isCreateInstruction(step)) {
       var contractToken = traceHelper.contractCreationToken(index)
@@ -81,12 +101,16 @@ TraceAnalyser.prototype.buildDepth = function (index, step, callStack) {
     this.traceCache.pushCallStack(index + 1, {
       callStack: callStack.slice(0)
     })
+    this.buildCalldata(index, step, tx, true)
   } else if (traceHelper.isReturnInstruction(step)) {
-    callStack.pop()
-    this.traceCache.pushCallChanges(step, index + 1)
-    this.traceCache.pushCallStack(index + 1, {
-      callStack: callStack.slice(0)
-    })
+    if (index + 1 < this.trace.length) {
+      callStack.pop()
+      this.traceCache.pushCallChanges(step, index + 1)
+      this.traceCache.pushCallStack(index + 1, {
+        callStack: callStack.slice(0)
+      })
+      this.buildCalldata(index, step, tx, false)
+    }
   }
 }
 
diff --git a/src/trace/traceCache.js b/src/trace/traceCache.js
index cce6d201a6..4942baf739 100644
--- a/src/trace/traceCache.js
+++ b/src/trace/traceCache.js
@@ -9,6 +9,7 @@ TraceCache.prototype.init = function () {
   this.callChanges = []
   this.returnChanges = []
   this.calls = {}
+  this.callsData = {}
   this.contractCreation = {}
 
   this.callDataChanges = []
@@ -18,8 +19,9 @@ TraceCache.prototype.init = function () {
   this.callStack = {} // contains all callStack by vmtrace index (we need to rebuild it, callstack is not included in the vmtrace)
 }
 
-TraceCache.prototype.pushCallDataChanges = function (value) {
+TraceCache.prototype.pushCallDataChanges = function (value, calldata) {
   this.callDataChanges.push(value)
+  this.callsData[value] = calldata
 }
 
 TraceCache.prototype.pushMemoryChanges = function (value) {
diff --git a/src/trace/traceManager.js b/src/trace/traceManager.js
index b7ab9a32bf..fb4c5be94e 100644
--- a/src/trace/traceManager.js
+++ b/src/trace/traceManager.js
@@ -101,7 +101,7 @@ TraceManager.prototype.getCallDataAt = function (stepIndex, callback) {
   }
   var callDataChange = traceHelper.findLowerBound(stepIndex, this.traceCache.callDataChanges)
   if (callDataChange === undefined) return callback('no calldata found', null)
-  callback(null, [this.trace[callDataChange].calldata])
+  callback(null, [this.traceCache.callsData[callDataChange]])
 }
 
 TraceManager.prototype.getCallStackAt = function (stepIndex, callback) {