diff --git a/lib/__snapshots__/bi-directional.test.ts.snap b/lib/__snapshots__/bi-directional.test.ts.snap
new file mode 100644
index 0000000..d5da447
--- /dev/null
+++ b/lib/__snapshots__/bi-directional.test.ts.snap
@@ -0,0 +1,6 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`bi-directional conversion should forward -1 back and forth 1`] = `
+"export type Num = 1000 | -1;
+"
+`;
diff --git a/lib/bi-directional.test.ts b/lib/bi-directional.test.ts
index 5754846..aa059b4 100644
--- a/lib/bi-directional.test.ts
+++ b/lib/bi-directional.test.ts
@@ -39,4 +39,18 @@ describe( "bi-directional conversion", ( ) =>
 
 		expect( epi ).toEqual( ts );
 	} );
+
+	it( "should forward -1 back and forth", ( ) =>
+	{
+		const ct = convertTypeScriptToCoreTypes(
+			`export type Num = 1000 | -1;`
+		);
+
+		const ts = convertCoreTypesToTypeScript(
+			ct.data,
+			{ noDescriptiveHeader: true, noDisableLintHeader: true }
+		);
+
+		expect( ts.data ).toMatchSnapshot( );
+	} );
 } );
diff --git a/lib/ts-to-core-types.test.ts b/lib/ts-to-core-types.test.ts
index 316ad2a..188d355 100644
--- a/lib/ts-to-core-types.test.ts
+++ b/lib/ts-to-core-types.test.ts
@@ -45,6 +45,22 @@ it( "object literal type", ( ) =>
 	] );
 } );
 
+it( "negative numeric literal type", ( ) =>
+{
+	const coreTypes = convertTypeScriptToCoreTypes( `
+	export type Foo = -1;
+	` ).data.types;
+
+	equal( coreTypes, [
+		{
+			name: 'Foo',
+			title: 'Foo',
+			type: 'number',
+			const: -1,
+		}
+	] );
+} );
+
 it( "basic interface with additional properties", ( ) =>
 {
 	const coreTypes = convertTypeScriptToCoreTypes( `
diff --git a/lib/ts-to-core-types.ts b/lib/ts-to-core-types.ts
index 4a18738..ce839f6 100644
--- a/lib/ts-to-core-types.ts
+++ b/lib/ts-to-core-types.ts
@@ -451,11 +451,23 @@ function fromTsTypeNode( node: ts.TypeNode, ctx: Context )
 		else if ( node.literal.kind === ts.SyntaxKind.NullKeyword )
 			return { type: 'null', ...decorateNode( node ) };
 
-		else if ( node.literal.kind === ts.SyntaxKind.PrefixUnaryExpression )
+		else if ( node.literal.kind === ts.SyntaxKind.PrefixUnaryExpression ) {
+			if (
+				"operand" in node.literal &&
+				node.literal.operator === ts.SyntaxKind.MinusToken
+			) {
+				return {
+					type: 'number',
+					const: -Number( node.literal.operand.getText( ) ),
+					...decorateNode( node ),
+				}
+			}
+
 			return ctx.handleError( ctx.getUnsupportedError(
-				"Prefix unary expressions not supported",
+				"Prefix unary expressions is only supported for MinusToken",
 				node.literal
 			) );
+		}
 
 		return ctx.handleError( ctx.getUnsupportedError(
 			"Literal type not understood",