diff --git a/readme.md b/readme.md
index 5bfdd72..28521b9 100644
--- a/readme.md
+++ b/readme.md
@@ -68,6 +68,9 @@ All the below methods accept a value and returns a boolean for whether the value
 ##### .null(value)
 ##### .string(value)
 ##### .number(value)
+
+Note: `is.number(NaN)` returns `false`.
+
 ##### .boolean(value)
 ##### .symbol(value)
 ##### .bigint(value)
diff --git a/source/index.ts b/source/index.ts
index 4cd388d..861b2f1 100644
--- a/source/index.ts
+++ b/source/index.ts
@@ -118,7 +118,7 @@ const isObject = (value: unknown): value is object => typeof value === 'object';
 
 is.undefined = isOfType<undefined>('undefined');
 is.string = isOfType<string>('string');
-is.number = isOfType<number>('number');
+is.number = (value: unknown): value is number => isOfType<number>('number')(value) && !is.nan(value);
 is.bigint = isOfType<bigint>('bigint');
 
 // eslint-disable-next-line @typescript-eslint/ban-types
diff --git a/test/test.ts b/test/test.ts
index ce01004..120e665 100644
--- a/test/test.ts
+++ b/test/test.ts
@@ -494,7 +494,7 @@ test('is.string', t => {
 });
 
 test('is.number', t => {
-	testType(t, 'number', ['nan', 'integer', 'safeInteger', 'infinite']);
+	testType(t, 'number', ['integer', 'safeInteger', 'infinite']);
 });
 
 // TODO: Nodejs 10 only