diff --git a/lib/reporters/tap.js b/lib/reporters/tap.js
index 2bcd995baa..f11dff5476 100644
--- a/lib/reporters/tap.js
+++ b/lib/reporters/tap.js
@@ -6,6 +6,7 @@
 var Base = require('./base')
   , cursor = Base.cursor
   , color = Base.color;
+var YAML = require('yamljs');
 
 /**
  * Expose `TAP`.
@@ -45,12 +46,13 @@ function TAP(runner) {
   runner.on('pass', function(test){
     passes++;
     console.log('ok %d %s', n, title(test));
+    writeDiagnostic(test);
   });
 
   runner.on('fail', function(test, err){
     failures++;
     console.log('not ok %d %s', n, title(test));
-    if (err.stack) console.log(err.stack.replace(/^/gm, '  '));
+    writeDiagnostic(test, err);
   });
 
   runner.on('end', function(){
@@ -71,3 +73,20 @@ function TAP(runner) {
 function title(test) {
   return test.fullTitle().replace(/#/g, '');
 }
+
+/**
+ * Output TAP diagnostic in YAML format
+ * @param {Object} test
+ * @param {Object} err
+ * @api private
+ */
+function writeDiagnostic(test, err){
+  var obj = {};
+  if (test.duration) obj.duration_ms = test.duration;
+  if (err && err.stack) obj.stacktrace = err.stack;
+  if (Object.keys(obj).length > 0) {
+    console.log('  ---');
+    console.log(YAML.stringify(obj, 4).replace(/^/gm, '  '));
+    console.log('  ...');
+  }
+}
diff --git a/package.json b/package.json
index 7352dee546..d8981532c3 100644
--- a/package.json
+++ b/package.json
@@ -33,7 +33,8 @@
     "diff": "1.0.7",
     "debug": "*",
     "mkdirp": "0.3.5",
-    "glob": "3.2.3"
+    "glob": "3.2.3",
+    "yamljs": "0.1.5"
   },
   "devDependencies": {
     "should": ">= 2.0.x",