diff --git a/source/index.ts b/source/index.ts
index 23c1829..b8f397c 100644
--- a/source/index.ts
+++ b/source/index.ts
@@ -136,8 +136,8 @@ namespace is { // tslint:disable-line:no-namespace
 	// tslint:enable:variable-name
 
 	export const nullOrUndefined = (value: any): value is null | undefined => null_(value) || undefined(value);
-	export const numericString = (value: string): boolean =>
-		!Number.isNaN(Number(value));
+	export const numericString = (value: any): boolean =>
+		string(value) && value.length > 0 && !Number.isNaN(Number(value));
 
 	export const array = Array.isArray;
 	export const buffer = isBuffer;
diff --git a/source/tests/test.ts b/source/tests/test.ts
index e57cb69..4285952 100644
--- a/source/tests/test.ts
+++ b/source/tests/test.ts
@@ -76,6 +76,14 @@ const types = new Map<string, Test>([
 			Symbol('🦄')
 		]
 	}],
+	['numericString', {
+		is: m.numericString,
+		fixtures: [
+			'5',
+			'-3.2',
+			'Infinity'
+		]
+	}],
 	['array', {
 		is: m.array,
 		fixtures: [
@@ -411,7 +419,7 @@ test('is.null', t => {
 });
 
 test('is.string', t => {
-	testType(t, 'string', ['emptyString']);
+	testType(t, 'string', ['emptyString', 'numericString']);
 });
 
 test('is.number', t => {
@@ -427,9 +435,9 @@ test('is.symbol', t => {
 });
 
 test('is.numericString', t => {
-	t.true(m.numericString('5'));
-	t.true(m.numericString('-3.2'));
-	t.true(m.numericString('Infinity'));
+	testType(t, 'numericString');
+	t.false(m.numericString(''));
+	t.false(m.numericString(1));
 });
 
 test('is.array', t => {