diff --git a/src/query.ts b/src/query.ts
index eb808dc0..3eccff86 100644
--- a/src/query.ts
+++ b/src/query.ts
@@ -21,7 +21,7 @@ export function parseQuery (parametersString: string = ""): QueryObject {
       continue;
     }
     const value = decodeQueryValue(s[2] || "");
-    if (object[key]) {
+    if (typeof object[key] !== "undefined") {
       if (Array.isArray(object[key])) {
         (object[key] as string[]).push(value);
       } else {
diff --git a/test/query.test.ts b/test/query.test.ts
index 20d0e6bc..48dbff78 100644
--- a/test/query.test.ts
+++ b/test/query.test.ts
@@ -27,7 +27,9 @@ describe("withQuery", () => {
       out: "/?str=%26&str2=%2526"
     },
     { input: "/?x=1,2,3", query: { y: "1,2,3" }, out: "/?x=1,2,3&y=1,2,3" },
-    { input: "http://a.com?v=1", query: { x: 2 }, out: "http://a.com?v=1&x=2" }
+    { input: "http://a.com?v=1", query: { x: 2 }, out: "http://a.com?v=1&x=2" },
+    { input: "/", query: { param: ["3", ""] }, out: "/?param=3&param=" },
+    { input: "/", query: { param: ["", "3"] }, out: "/?param=&param=3" }
   ];
 
   for (const t of tests) {
@@ -39,7 +41,9 @@ describe("withQuery", () => {
 
 describe("getQuery", () => {
   const tests = {
-    "http://foo.com/foo?test=123&unicode=%E5%A5%BD": { test: "123", unicode: "好" }
+    "http://foo.com/foo?test=123&unicode=%E5%A5%BD": { test: "123", unicode: "好" },
+    "http://foo.com/?param=3&param=": { param: ["3", ""] },
+    "http://foo.com/?param=&param=3": { param: ["", "3"] }
   };
 
   for (const t in tests) {