diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index de08b209d3e..4f07331a98e 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -1346,7 +1346,9 @@ namespace ts {
 
             emitExpression(node.left);
             increaseIndentIf(indentBeforeOperator, isCommaOperator ? " " : undefined);
+            emitLeadingCommentsOfPosition(node.operatorToken.pos);
             writeTokenNode(node.operatorToken);
+            emitTrailingCommentsOfPosition(node.operatorToken.end);
             increaseIndentIf(indentAfterOperator, " ");
             emitExpression(node.right);
             decreaseIndentIf(indentBeforeOperator, indentAfterOperator);
diff --git a/tests/baselines/reference/commentOnBinaryOperator1.js b/tests/baselines/reference/commentOnBinaryOperator1.js
new file mode 100644
index 00000000000..daad6f5bdde
--- /dev/null
+++ b/tests/baselines/reference/commentOnBinaryOperator1.js
@@ -0,0 +1,25 @@
+//// [commentOnBinaryOperator1.ts]
+var a = 'some'
+    // comment
+    + 'text';
+
+var b = 'some'
+    /* comment */
+    + 'text';
+
+var c = 'some'
+    /* comment */
+    + /*comment1*/
+    'text';
+
+//// [commentOnBinaryOperator1.js]
+var a = 'some'
+    // comment
+    + 'text';
+var b = 'some'
+    /* comment */
+    + 'text';
+var c = 'some'
+    /* comment */
+    +/*comment1*/ 
+        'text';
diff --git a/tests/baselines/reference/commentOnBinaryOperator1.symbols b/tests/baselines/reference/commentOnBinaryOperator1.symbols
new file mode 100644
index 00000000000..db92e4e4fc5
--- /dev/null
+++ b/tests/baselines/reference/commentOnBinaryOperator1.symbols
@@ -0,0 +1,19 @@
+=== tests/cases/compiler/commentOnBinaryOperator1.ts ===
+var a = 'some'
+>a : Symbol(a, Decl(commentOnBinaryOperator1.ts, 0, 3))
+
+    // comment
+    + 'text';
+
+var b = 'some'
+>b : Symbol(b, Decl(commentOnBinaryOperator1.ts, 4, 3))
+
+    /* comment */
+    + 'text';
+
+var c = 'some'
+>c : Symbol(c, Decl(commentOnBinaryOperator1.ts, 8, 3))
+
+    /* comment */
+    + /*comment1*/
+    'text';
diff --git a/tests/baselines/reference/commentOnBinaryOperator1.types b/tests/baselines/reference/commentOnBinaryOperator1.types
new file mode 100644
index 00000000000..59724d42f51
--- /dev/null
+++ b/tests/baselines/reference/commentOnBinaryOperator1.types
@@ -0,0 +1,29 @@
+=== tests/cases/compiler/commentOnBinaryOperator1.ts ===
+var a = 'some'
+>a : string
+>'some'    // comment    + 'text' : string
+>'some' : "some"
+
+    // comment
+    + 'text';
+>'text' : "text"
+
+var b = 'some'
+>b : string
+>'some'    /* comment */    + 'text' : string
+>'some' : "some"
+
+    /* comment */
+    + 'text';
+>'text' : "text"
+
+var c = 'some'
+>c : string
+>'some'    /* comment */    + /*comment1*/    'text' : string
+>'some' : "some"
+
+    /* comment */
+    + /*comment1*/
+    'text';
+>'text' : "text"
+
diff --git a/tests/baselines/reference/commentOnBinaryOperator2.js b/tests/baselines/reference/commentOnBinaryOperator2.js
new file mode 100644
index 00000000000..5d87ddccbef
--- /dev/null
+++ b/tests/baselines/reference/commentOnBinaryOperator2.js
@@ -0,0 +1,22 @@
+//// [commentOnBinaryOperator2.ts]
+var a = 'some'
+    // comment
+    + 'text';
+
+var b = 'some'
+    /* comment */
+    + 'text';
+
+var c = 'some'
+    /* comment */
+    + /*comment1*/
+    'text';
+
+//// [commentOnBinaryOperator2.js]
+var a = 'some'
+    + 'text';
+var b = 'some'
+    + 'text';
+var c = 'some'
+    +
+        'text';
diff --git a/tests/baselines/reference/commentOnBinaryOperator2.symbols b/tests/baselines/reference/commentOnBinaryOperator2.symbols
new file mode 100644
index 00000000000..10a0e94dd36
--- /dev/null
+++ b/tests/baselines/reference/commentOnBinaryOperator2.symbols
@@ -0,0 +1,19 @@
+=== tests/cases/compiler/commentOnBinaryOperator2.ts ===
+var a = 'some'
+>a : Symbol(a, Decl(commentOnBinaryOperator2.ts, 0, 3))
+
+    // comment
+    + 'text';
+
+var b = 'some'
+>b : Symbol(b, Decl(commentOnBinaryOperator2.ts, 4, 3))
+
+    /* comment */
+    + 'text';
+
+var c = 'some'
+>c : Symbol(c, Decl(commentOnBinaryOperator2.ts, 8, 3))
+
+    /* comment */
+    + /*comment1*/
+    'text';
diff --git a/tests/baselines/reference/commentOnBinaryOperator2.types b/tests/baselines/reference/commentOnBinaryOperator2.types
new file mode 100644
index 00000000000..411c8c69b8a
--- /dev/null
+++ b/tests/baselines/reference/commentOnBinaryOperator2.types
@@ -0,0 +1,29 @@
+=== tests/cases/compiler/commentOnBinaryOperator2.ts ===
+var a = 'some'
+>a : string
+>'some'    // comment    + 'text' : string
+>'some' : "some"
+
+    // comment
+    + 'text';
+>'text' : "text"
+
+var b = 'some'
+>b : string
+>'some'    /* comment */    + 'text' : string
+>'some' : "some"
+
+    /* comment */
+    + 'text';
+>'text' : "text"
+
+var c = 'some'
+>c : string
+>'some'    /* comment */    + /*comment1*/    'text' : string
+>'some' : "some"
+
+    /* comment */
+    + /*comment1*/
+    'text';
+>'text' : "text"
+
diff --git a/tests/baselines/reference/commentsArgumentsOfCallExpression2.js b/tests/baselines/reference/commentsArgumentsOfCallExpression2.js
index a7065410ff4..e05256b86b6 100644
--- a/tests/baselines/reference/commentsArgumentsOfCallExpression2.js
+++ b/tests/baselines/reference/commentsArgumentsOfCallExpression2.js
@@ -14,7 +14,7 @@ foo(
 function foo(/*c1*/ x, /*d1*/ y, /*e1*/ w) { }
 var a, b;
 foo(/*c2*/ 1, /*d2*/ 1 + 2, /*e1*/ a + b);
-foo(/*c3*/ function () { }, /*d2*/ function () { }, /*e2*/ a + b);
+foo(/*c3*/ function () { }, /*d2*/ function () { }, /*e2*/ a +/*e3*/  b);
 foo(/*c3*/ function () { }, /*d3*/ function () { }, /*e3*/ (a + b));
 foo(
 /*c4*/ function () { }, 
diff --git a/tests/baselines/reference/parser15.4.4.14-9-2.js b/tests/baselines/reference/parser15.4.4.14-9-2.js
index 0f533cd9a26..e24da870d3e 100644
--- a/tests/baselines/reference/parser15.4.4.14-9-2.js
+++ b/tests/baselines/reference/parser15.4.4.14-9-2.js
@@ -41,9 +41,9 @@ function testcase() {
     var one = 1;
     var _float = -(4 / 3);
     var a = new Array(false, undefined, null, "0", obj, -1.3333333333333, "str", -0, true, +0, one, 1, 0, false, _float, -(4 / 3));
-    if (a.indexOf(-(4 / 3)) === 14 &&
-        a.indexOf(0) === 7 &&
-        a.indexOf(-0) === 7 &&
+    if (a.indexOf(-(4 / 3)) === 14 &&// a[14]=_float===-(4/3)
+        a.indexOf(0) === 7 &&// a[7] = +0, 0===+0
+        a.indexOf(-0) === 7 &&// a[7] = +0, -0===+0
         a.indexOf(1) === 10) {
         return true;
     }
diff --git a/tests/baselines/reference/parserGreaterThanTokenAmbiguity10.js b/tests/baselines/reference/parserGreaterThanTokenAmbiguity10.js
index 862722b1a73..7ff9e380dcf 100644
--- a/tests/baselines/reference/parserGreaterThanTokenAmbiguity10.js
+++ b/tests/baselines/reference/parserGreaterThanTokenAmbiguity10.js
@@ -6,5 +6,6 @@
 
 //// [parserGreaterThanTokenAmbiguity10.js]
 1
-    >>>
+    // before
+    >>>// after
         2;
diff --git a/tests/baselines/reference/parserGreaterThanTokenAmbiguity15.js b/tests/baselines/reference/parserGreaterThanTokenAmbiguity15.js
index b6f905e12e7..03e6211ae15 100644
--- a/tests/baselines/reference/parserGreaterThanTokenAmbiguity15.js
+++ b/tests/baselines/reference/parserGreaterThanTokenAmbiguity15.js
@@ -6,5 +6,6 @@
 
 //// [parserGreaterThanTokenAmbiguity15.js]
 1
-    >>=
+    // before
+    >>=// after
         2;
diff --git a/tests/baselines/reference/parserGreaterThanTokenAmbiguity20.js b/tests/baselines/reference/parserGreaterThanTokenAmbiguity20.js
index 01d1d6401f2..ba5e380043d 100644
--- a/tests/baselines/reference/parserGreaterThanTokenAmbiguity20.js
+++ b/tests/baselines/reference/parserGreaterThanTokenAmbiguity20.js
@@ -6,5 +6,6 @@
 
 //// [parserGreaterThanTokenAmbiguity20.js]
 1
-    >>>=
+    // Before
+    >>>=// after
         2;
diff --git a/tests/baselines/reference/parserGreaterThanTokenAmbiguity5.js b/tests/baselines/reference/parserGreaterThanTokenAmbiguity5.js
index c65b76f504a..e240746caa4 100644
--- a/tests/baselines/reference/parserGreaterThanTokenAmbiguity5.js
+++ b/tests/baselines/reference/parserGreaterThanTokenAmbiguity5.js
@@ -6,5 +6,6 @@
 
 //// [parserGreaterThanTokenAmbiguity5.js]
 1
-    >>
+    // before
+    >>// after
         2;
diff --git a/tests/baselines/reference/typeGuardsInConditionalExpression.js b/tests/baselines/reference/typeGuardsInConditionalExpression.js
index 9aade91612a..8be83a887b1 100644
--- a/tests/baselines/reference/typeGuardsInConditionalExpression.js
+++ b/tests/baselines/reference/typeGuardsInConditionalExpression.js
@@ -138,7 +138,7 @@ function foo8(x) {
     var b;
     return typeof x === "string"
         ? x === "hello"
-        : ((b = x) &&
+        : ((b = x) &&//  number | boolean
             (typeof x === "boolean"
                 ? x // boolean
                 : x == 10)); // boolean
diff --git a/tests/cases/compiler/commentOnBinaryOperator1.ts b/tests/cases/compiler/commentOnBinaryOperator1.ts
new file mode 100644
index 00000000000..29de3410c32
--- /dev/null
+++ b/tests/cases/compiler/commentOnBinaryOperator1.ts
@@ -0,0 +1,12 @@
+var a = 'some'
+    // comment
+    + 'text';
+
+var b = 'some'
+    /* comment */
+    + 'text';
+
+var c = 'some'
+    /* comment */
+    + /*comment1*/
+    'text';
\ No newline at end of file
diff --git a/tests/cases/compiler/commentOnBinaryOperator2.ts b/tests/cases/compiler/commentOnBinaryOperator2.ts
new file mode 100644
index 00000000000..023655e16c0
--- /dev/null
+++ b/tests/cases/compiler/commentOnBinaryOperator2.ts
@@ -0,0 +1,13 @@
+// @removeComments: true
+var a = 'some'
+    // comment
+    + 'text';
+
+var b = 'some'
+    /* comment */
+    + 'text';
+
+var c = 'some'
+    /* comment */
+    + /*comment1*/
+    'text';
\ No newline at end of file