diff --git a/lib/index.js b/lib/index.js
index 314f937..2fb0827 100755
--- a/lib/index.js
+++ b/lib/index.js
@@ -2167,6 +2167,44 @@ addMethod('doto', function (f) {
 Stream.prototype.tap = Stream.prototype.doto;
 _.tap = _.doto;
 
+/**
+ * Applies a function, which must return a (possibly empty) highland stream, to each value from the source, and re-emits the
+ * source value when the function return ends.
+ *
+ * @id flatTap
+ * @section Transforms
+ * @name Stream.flatTap(f)
+ * @param {Function} f - the function to apply
+ * @api public
+ *
+ * const httpLog = _(new Promnise(res => {
+ *  setTimeout(() => {
+ *    console.log('Log');
+ *    res('Success')
+ *  }, 3000)
+ * }))
+ *
+ * _([1, 2, 3]).flatTap(httpLog)   // Will emit [1,2,3]
+ */
+
+addMethod('flatTap', function (f) {
+    return this.flatMap(function (x) {
+        return f(x).consume(function (err, y, push, next) {
+            if (err) {
+                push(err);
+                push(null, _.nil);
+            }
+            else if (y === _.nil) {
+                push(null, x);
+                push(null, _.nil);
+            }
+            else {
+                next();
+            }
+        });
+    });
+});
+
 /**
  * Limits number of values through the stream to a maximum of number of values
  * per window. Errors are not limited but allowed to pass through as soon as
diff --git a/test/test.js b/test/test.js
index 467ecf3..7aaa0d5 100755
--- a/test/test.js
+++ b/test/test.js
@@ -4909,6 +4909,117 @@ exports['tap - doto alias'] = function (test) {
     test.done();
 };
 
+
+exports.flatTap = {
+    'flatTap - noValueOnError': noValueOnErrorTest(_.flatTap(function (x) { return _(); })),
+    'flatTap - returnsSameStream': returnsSameStreamTest(function (s) {
+        return s.flatTap(function (x) { return _([2]); });
+    }, [1], [1]),
+    'flatTap - On a empty stream': function (test) {
+        test.expect(1);
+        var s = _([]).flatTap(function (x) {
+            return _([6]);
+        });
+
+        s.pull(valueEquals(test, _.nil));
+        test.done();
+    },
+    'flatTap - Returns an Empty stream': function (test) {
+        test.expect(1);
+        var s = _([3]).flatTap(function (x) {
+            return _([]);
+        });
+
+        s.pull(valueEquals(test, 3));
+        test.done();
+    },
+    'flatTap - Emits an multiple values': function (test) {
+        test.expect(1);
+        var s = _([3]).flatTap(function (x) {
+            return _([5, 6, 7, 8]);
+        });
+
+        s.pull(valueEquals(test, 3));
+        test.done();
+    },
+    'flatTap - Emits an error values': function (test) {
+        test.expect(4);
+        var s = _([1, 2, 3, 4]).flatTap(function (x) {
+            return _(function (push) {
+                push({errorMessage: 'error'});
+                push(null, _.nil);
+            });
+        });
+
+        s.pull(anyError(test));
+        s.pull(anyError(test));
+        s.pull(anyError(test));
+        s.pull(anyError(test));
+        test.done();
+    },
+    'flatTap - argument function throws': function (test) {
+        test.expect(4);
+        var err = new Error('error');
+        var s = _([1, 2, 3, 4]).flatTap(function (x) {
+            if (x === 1) { throw err; }
+            if (x === 2) { _(['hello']); }
+            if (x === 3) { throw err; }
+            return _(['world']);
+        });
+
+        s.pull(errorEquals(test, 'error'));
+        s.pull(valueEquals(test, 2));
+        s.pull(anyError(test));
+        s.pull(valueEquals(test, 4));
+        test.done();
+    },
+    'flatTap - ArrayStream': function (test) {
+        var seen = [];
+        var f = function (x) {
+            return _(function (push, next) {
+                setTimeout(function () {
+                    var y = x * 2;
+                    seen.push(y);
+                    push(null, y);
+                    push(null, _.nil);
+                }, 10);
+            });
+        };
+        _([1, 2, 3, 4]).flatTap(f).toArray(function (xs) {
+            test.same(xs, [1, 2, 3, 4]);
+            test.same(seen, [2, 4, 6, 8]);
+            test.done();
+        });
+    },
+    'flatTap - GeneratorStream': function (test) {
+        var seen = [];
+        var f = function (x) {
+            return _(function (push, next) {
+                setTimeout(function () {
+                    var y = x * 2;
+                    seen.push(y);
+                    push(null, y);
+                    push(null, _.nil);
+                }, 10);
+            });
+        };
+        var s = _(function (push, next) {
+            push(null, 1);
+            setTimeout(function () {
+                push(null, 2);
+                push(null, 3);
+                push(null, 4);
+                push(null, _.nil);
+            }, 10);
+        });
+        s.flatTap(f).toArray(function (xs) {
+            test.same(xs, [1, 2, 3, 4]);
+            test.same(seen, [2, 4, 6, 8]);
+            test.done();
+        });
+    }
+};
+
 exports.flatMap = function (test) {
     var f = function (x) {
         return _(function (push, next) {