diff --git a/implementation-contributed/v8/mjsunit/harmony/to-number.js b/implementation-contributed/v8/mjsunit/harmony/to-number.js
index a48a7d83f8c..c5a06cf4ffe 100644
--- a/implementation-contributed/v8/mjsunit/harmony/to-number.js
+++ b/implementation-contributed/v8/mjsunit/harmony/to-number.js
@@ -19,6 +19,7 @@ assertEquals(NaN, %ToNumber(undefined));
 assertEquals(-1, %ToNumber("-1"));
 assertEquals(123, %ToNumber("123"));
 assertEquals(NaN, %ToNumber("random text"));
+assertEquals(NaN, %ToNumber("INFINITY"));
 
 assertThrows(function() { %ToNumber(Symbol.toPrimitive) }, TypeError);
 
diff --git a/test/built-ins/Number/S15.7.1.1_A1.js b/test/built-ins/Number/S15.7.1.1_A1.js
index 3ccfaf32ae3..ebecc20106c 100644
--- a/test/built-ins/Number/S15.7.1.1_A1.js
+++ b/test/built-ins/Number/S15.7.1.1_A1.js
@@ -24,3 +24,4 @@ assert.sameValue(
 );
 
 assert.sameValue(Number("abc"), NaN, 'Number("abc") returns NaN');
+assert.sameValue(Number("INFINITY"), NaN, 'Number("INFINITY") returns NaN');
diff --git a/test/language/expressions/unary-plus/S11.4.6_A3_T3.js b/test/language/expressions/unary-plus/S11.4.6_A3_T3.js
index 79bf732a2f2..cb6c4546156 100644
--- a/test/language/expressions/unary-plus/S11.4.6_A3_T3.js
+++ b/test/language/expressions/unary-plus/S11.4.6_A3_T3.js
@@ -13,11 +13,16 @@ if (+"1" !== 1) {
 }
 
 //CHECK#2
-if (isNaN(+"x") !== true) {
-  throw new Test262Error('#2: +"x" === Not-a-Number. Actual: ' + (+"x"));
+if (+new Number("-1") !== -1) {
+  throw new Test262Error('#2: +new String("-1") === -1. Actual: ' + (+new String("-1")));
 }
 
 //CHECK#3
-if (+new Number("-1") !== -1) {
-  throw new Test262Error('#3: +new String("-1") === -1. Actual: ' + (+new String("-1")));
+if (isNaN(+"x") !== true) {
+  throw new Test262Error('#3: +"x" === Not-a-Number. Actual: ' + (+"x"));
+}
+
+//CHECK#4
+if (isNaN(+"INFINITY") !== true) {
+  throw new Test262Error('#4: +"INFINITY" === Not-a-Number. Actual: ' + (+"INFINITY"));
 }