diff --git a/src/main/scala/gitbucket/core/api/AddLabelsToAnIssue.scala b/src/main/scala/gitbucket/core/api/AddLabelsToAnIssue.scala
new file mode 100644
index 0000000..cd6f5eb
--- /dev/null
+++ b/src/main/scala/gitbucket/core/api/AddLabelsToAnIssue.scala
@@ -0,0 +1,6 @@
+package gitbucket.core.api
+
+/**
+ * https://developer.github.com/v3/issues/labels/#add-labels-to-an-issue
+ */
+case class AddLabelsToAnIssue(labels: Seq[String])
diff --git a/src/main/scala/gitbucket/core/controller/api/ApiIssueLabelControllerBase.scala b/src/main/scala/gitbucket/core/controller/api/ApiIssueLabelControllerBase.scala
index 688b498..b06dcee 100644
--- a/src/main/scala/gitbucket/core/controller/api/ApiIssueLabelControllerBase.scala
+++ b/src/main/scala/gitbucket/core/controller/api/ApiIssueLabelControllerBase.scala
@@ -1,5 +1,5 @@
 package gitbucket.core.controller.api
-import gitbucket.core.api.{ApiError, ApiLabel, CreateALabel, JsonFormat}
+import gitbucket.core.api.{AddLabelsToAnIssue, ApiError, ApiLabel, CreateALabel, JsonFormat}
 import gitbucket.core.controller.ControllerBase
 import gitbucket.core.service._
 import gitbucket.core.util.Implicits._
@@ -121,10 +121,10 @@
    */
   post("/api/v3/repos/:owner/:repository/issues/:id/labels")(writableUsersOnly { repository =>
     JsonFormat(for {
-      data <- extractFromJsonBody[Seq[String]]
+      data <- extractFromJsonBody[AddLabelsToAnIssue]
       issueId <- params("id").toIntOpt
     } yield {
-      data.map { labelName =>
+      data.labels.map { labelName =>
         val label = getLabel(repository.owner, repository.name, labelName).getOrElse(
           getLabel(
             repository.owner,
@@ -160,11 +160,11 @@
    */
   put("/api/v3/repos/:owner/:repository/issues/:id/labels")(writableUsersOnly { repository =>
     JsonFormat(for {
-      data <- extractFromJsonBody[Seq[String]]
+      data <- extractFromJsonBody[AddLabelsToAnIssue]
       issueId <- params("id").toIntOpt
     } yield {
       deleteAllIssueLabels(repository.owner, repository.name, issueId, true)
-      data.map { labelName =>
+      data.labels.map { labelName =>
         val label = getLabel(repository.owner, repository.name, labelName).getOrElse(
           getLabel(
             repository.owner,
diff --git a/src/test/scala/gitbucket/core/api/ApiIntegrationTest.scala b/src/test/scala/gitbucket/core/api/ApiIntegrationTest.scala
index 2b34dbf..97933a4 100644
--- a/src/test/scala/gitbucket/core/api/ApiIntegrationTest.scala
+++ b/src/test/scala/gitbucket/core/api/ApiIntegrationTest.scala
@@ -204,4 +204,75 @@
     }
   }
 
+  test("issue labels") {
+    Using.resource(new TestingGitBucketServer(19999)) { server =>
+      val github = server.client("root", "root")
+
+      val repo = github.createRepository("issue_label_test").autoInit(true).create()
+      val issue = repo.createIssue("test").create()
+
+      // Initial label state
+      {
+        val labels = repo.getIssue(issue.getNumber).getLabels
+        assert(labels.size() == 0)
+      }
+
+      // Add labels
+      {
+        issue.addLabels("bug", "duplicate")
+
+        val labels = repo.getIssue(issue.getNumber).getLabels
+        assert(labels.size() == 2)
+
+        val i = labels.iterator()
+        val label1 = i.next()
+        assert(label1.getName == "bug")
+        assert(label1.getColor == "fc2929")
+        assert(label1.getUrl == "http://localhost:19999/api/v3/repos/root/issue_label_test/labels/bug")
+
+        val label2 = i.next()
+        assert(label2.getName == "duplicate")
+        assert(label2.getColor == "cccccc")
+        assert(label2.getUrl == "http://localhost:19999/api/v3/repos/root/issue_label_test/labels/duplicate")
+      }
+
+      // Remove a label
+      {
+        issue.removeLabel("duplicate")
+
+        val labels = repo.getIssue(issue.getNumber).getLabels
+        assert(labels.size() == 1)
+
+        val i = labels.iterator()
+        val label1 = i.next()
+        assert(label1.getName == "bug")
+        assert(label1.getColor == "fc2929")
+        assert(label1.getUrl == "http://localhost:19999/api/v3/repos/root/issue_label_test/labels/bug")
+      }
+
+    // Replace labels (Cannot test because GHLabel.setLabels() doesn't use the replace endpoint)
+//      {
+//        issue.setLabels("enhancement", "invalid", "question")
+//
+//        val labels = repo.getIssue(issue.getNumber).getLabels
+//        assert(labels.size() == 3)
+//
+//        val i = labels.iterator()
+//        val label1 = i.next()
+//        assert(label1.getName == "enhancement")
+//        assert(label1.getColor == "84b6eb")
+//        assert(label1.getUrl == "http://localhost:19999/api/v3/repos/root/issue_label_test/labels/enhancement")
+//
+//        val label2 = i.next()
+//        assert(label2.getName == "invalid")
+//        assert(label2.getColor == "e6e6e6")
+//        assert(label2.getUrl == "http://localhost:19999/api/v3/repos/root/issue_label_test/labels/invalid")
+//
+//        val label3 = i.next()
+//        assert(label3.getName == "question")
+//        assert(label3.getColor == "cc317c")
+//        assert(label3.getUrl == "http://localhost:19999/api/v3/repos/root/issue_label_test/labels/question")
+//      }
+    }
+  }
 }