diff --git a/IPython/html/nbconvert/tests/test_nbconvert_handlers.py b/IPython/html/nbconvert/tests/test_nbconvert_handlers.py
index 904bc9897..4fb270529 100644
--- a/IPython/html/nbconvert/tests/test_nbconvert_handlers.py
+++ b/IPython/html/nbconvert/tests/test_nbconvert_handlers.py
@@ -60,7 +60,7 @@ class APITest(NotebookTestBase):
         cc1.outputs.append(new_output(output_type="stream", data=u'12'))
         cc1.outputs.append(new_output(output_type="execute_result",
             mime_bundle={'image/png' : png_green_pixel},
-            prompt_number=1,
+            execution_count=1,
         ))
         nb.cells.append(cc1)
         
diff --git a/IPython/html/static/notebook/js/codecell.js b/IPython/html/static/notebook/js/codecell.js
index ca5b6f399..8ae55b5bb 100644
--- a/IPython/html/static/notebook/js/codecell.js
+++ b/IPython/html/static/notebook/js/codecell.js
@@ -471,7 +471,7 @@ define([
                 this.code_mirror.clearHistory();
                 this.auto_highlight();
             }
-            this.set_input_prompt(data.prompt_number);
+            this.set_input_prompt(data.execution_count);
             this.output_area.trusted = data.metadata.trusted || false;
             this.output_area.fromJSON(data.outputs);
             if (data.metadata.collapsed !== undefined) {
@@ -490,9 +490,9 @@ define([
         data.source = this.get_text();
         // is finite protect against undefined and '*' value
         if (isFinite(this.input_prompt_number)) {
-            data.prompt_number = this.input_prompt_number;
+            data.execution_count = this.input_prompt_number;
         } else {
-            data.prompt_number = null;
+            data.execution_count = null;
         }
         var outputs = this.output_area.toJSON();
         data.outputs = outputs;
diff --git a/IPython/html/static/notebook/js/outputarea.js b/IPython/html/static/notebook/js/outputarea.js
index 373256313..81c49edec 100644
--- a/IPython/html/static/notebook/js/outputarea.js
+++ b/IPython/html/static/notebook/js/outputarea.js
@@ -220,7 +220,7 @@ define([
             json = content.data;
             json.output_type = msg_type;
             json.metadata = content.metadata;
-            json.prompt_number = content.execution_count;
+            json.execution_count = content.execution_count;
         } else if (msg_type === "error") {
             json.ename = content.ename;
             json.evalue = content.evalue;
@@ -414,7 +414,7 @@ define([
 
 
     OutputArea.prototype.append_execute_result = function (json) {
-        var n = json.prompt_number || ' ';
+        var n = json.execution_count || ' ';
         var toinsert = this.create_output_area();
         if (this.prompt_area) {
             toinsert.find('div.prompt').addClass('output_prompt').text('Out[' + n + ']:');
diff --git a/IPython/html/tests/notebook/inject_js.js b/IPython/html/tests/notebook/inject_js.js
index 4f72a3659..03757aa79 100644
--- a/IPython/html/tests/notebook/inject_js.js
+++ b/IPython/html/tests/notebook/inject_js.js
@@ -13,7 +13,7 @@ casper.notebook_test(function () {
     this.evaluate(function () {
         var cell = IPython.notebook.get_cell(0);
         var json = cell.toJSON();
-        json.prompt_number = "<script> alert('hello from input prompts !')</script>";
+        json.execution_count = "<script> alert('hello from input prompts !')</script>";
         cell.fromJSON(json);
     });