diff --git a/src/printer.js b/src/printer.js
index 3e5b5f5c..06ada672 100644
--- a/src/printer.js
+++ b/src/printer.js
@@ -2300,6 +2300,7 @@ function genericPrintNoParens(path, options, print, args) {
     case "TSParenthesizedType":
       return concat(["(", path.call(print, "typeAnnotation"), ")"]);
     case "TSIndexSignature": {
+      const parent = path.getParentNode();
       let printedParams = [];
       if (n.params) {
         printedParams = path.map(print, "params");
@@ -2319,7 +2320,8 @@ function genericPrintNoParens(path, options, print, args) {
         // it using parseDelimitedList that uses commas as delimiter.
         join(", ", printedParams),
         "]: ",
-        path.call(print, "typeAnnotation")
+        path.call(print, "typeAnnotation"),
+        parent.type === "ClassBody" ? semi : ""
       ]);
     }
     case "TSTypePredicate":
diff --git a/tests/typescript_index_signature/__snapshots__/jsfmt.spec.js.snap b/tests/typescript_index_signature/__snapshots__/jsfmt.spec.js.snap
new file mode 100644
index 00000000..76878611
--- /dev/null
+++ b/tests/typescript_index_signature/__snapshots__/jsfmt.spec.js.snap
@@ -0,0 +1,14 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`index-signature.ts 1`] = `
+class LocalStorage implements Storage {
+  [index: number]: string;
+  [key: string]: any;
+}
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+class LocalStorage implements Storage {
+  [index: number]: string;
+  [key: string]: any;
+}
+
+`;
diff --git a/tests/typescript_index_signature/index-signature.ts b/tests/typescript_index_signature/index-signature.ts
new file mode 100644
index 00000000..ebe06818
--- /dev/null
+++ b/tests/typescript_index_signature/index-signature.ts
@@ -0,0 +1,4 @@
+class LocalStorage implements Storage {
+  [index: number]: string;
+  [key: string]: any;
+}
diff --git a/tests/typescript_index_signature/jsfmt.spec.js b/tests/typescript_index_signature/jsfmt.spec.js
new file mode 100644
index 00000000..bc085c48
--- /dev/null
+++ b/tests/typescript_index_signature/jsfmt.spec.js
@@ -0,0 +1 @@
+run_spec(__dirname, { parser: "typescript" });
diff --git a/tests/typescript_nosemi/__snapshots__/jsfmt.spec.js.snap b/tests/typescript_nosemi/__snapshots__/jsfmt.spec.js.snap
index 6db6d27e..5c73500c 100644
--- a/tests/typescript_nosemi/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/typescript_nosemi/__snapshots__/jsfmt.spec.js.snap
@@ -1,5 +1,18 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`index-signature.ts 1`] = `
+class LocalStorage implements Storage {
+  [index: number]: string;
+  [key: string]: any;
+}
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+class LocalStorage implements Storage {
+  [index: number]: string
+  [key: string]: any
+}
+
+`;
+
 exports[`interface.ts 1`] = `
 interface Inline { x: string }
 
diff --git a/tests/typescript_nosemi/index-signature.ts b/tests/typescript_nosemi/index-signature.ts
new file mode 100644
index 00000000..ebe06818
--- /dev/null
+++ b/tests/typescript_nosemi/index-signature.ts
@@ -0,0 +1,4 @@
+class LocalStorage implements Storage {
+  [index: number]: string;
+  [key: string]: any;
+}