diff --git a/lib/pleroma/web/mastodon_api/mastodon_api_controller.ex b/lib/pleroma/web/mastodon_api/mastodon_api_controller.ex
index 881bd38df..5e299c976 100644
--- a/lib/pleroma/web/mastodon_api/mastodon_api_controller.ex
+++ b/lib/pleroma/web/mastodon_api/mastodon_api_controller.ex
@@ -311,6 +311,30 @@ def unfollow(%{assigns: %{user: follower}} = conn, %{"id" => id}) do
     end
   end
 
+  def block(%{assigns: %{user: blocker}} = conn, %{"id" => id}) do
+    with %User{} = blocked <- Repo.get(User, id),
+         {:ok, blocker} <- User.block(blocker, blocked) do
+      render conn, AccountView, "relationship.json", %{user: blocker, target: blocked}
+    else
+      {:error, message} = err ->
+        conn
+        |> put_resp_content_type("application/json")
+        |> send_resp(403, Poison.encode!(%{"error" => message}))
+    end
+  end
+
+  def unblock(%{assigns: %{user: blocker}} = conn, %{"id" => id}) do
+    with %User{} = blocked <- Repo.get(User, id),
+         {:ok, blocker} <- User.unblock(blocker, blocked) do
+      render conn, AccountView, "relationship.json", %{user: blocker, target: blocked}
+    else
+      {:error, message} = err ->
+        conn
+        |> put_resp_content_type("application/json")
+        |> send_resp(403, Poison.encode!(%{"error" => message}))
+    end
+  end
+
   def search(%{assigns: %{user: user}} = conn, %{"q" => query} = params) do
     accounts = User.search(query, params["resolve"] == "true")
 
diff --git a/lib/pleroma/web/router.ex b/lib/pleroma/web/router.ex
index 1fb5eadf6..c4bbaa265 100644
--- a/lib/pleroma/web/router.ex
+++ b/lib/pleroma/web/router.ex
@@ -58,8 +58,8 @@ def user_fetcher(username) do
     get "/accounts/search", MastodonAPIController, :account_search
     post "/accounts/:id/follow", MastodonAPIController, :follow
     post "/accounts/:id/unfollow", MastodonAPIController, :unfollow
-    post "/accounts/:id/block", MastodonAPIController, :relationship_noop
-    post "/accounts/:id/unblock", MastodonAPIController, :relationship_noop
+    post "/accounts/:id/block", MastodonAPIController, :block
+    post "/accounts/:id/unblock", MastodonAPIController, :unblock
     post "/accounts/:id/mute", MastodonAPIController, :relationship_noop
     post "/accounts/:id/unmute", MastodonAPIController, :relationship_noop
 
diff --git a/test/web/mastodon_api/mastodon_api_controller_test.exs b/test/web/mastodon_api/mastodon_api_controller_test.exs
index cf09bc4b8..c91f96f38 100644
--- a/test/web/mastodon_api/mastodon_api_controller_test.exs
+++ b/test/web/mastodon_api/mastodon_api_controller_test.exs
@@ -291,11 +291,29 @@ test "following / unfollowing a user", %{conn: conn} do
     assert id == other_user.id
   end
 
-  test "unimplemented block/mute endpoints" do
+  test "blocking / unblocking a user", %{conn: conn} do
     user = insert(:user)
     other_user = insert(:user)
 
-    ["block", "unblock", "mute", "unmute"]
+    conn = conn
+    |> assign(:user, user)
+    |> post("/api/v1/accounts/#{other_user.id}/block")
+
+    assert %{"id" => id, "blocking" => true} = json_response(conn, 200)
+
+    user = Repo.get(User, user.id)
+    conn = build_conn()
+    |> assign(:user, user)
+    |> post("/api/v1/accounts/#{other_user.id}/unblock")
+
+    assert %{"id" => id, "blocking" => false} = json_response(conn, 200)
+  end
+
+  test "unimplemented mute endpoints" do
+    user = insert(:user)
+    other_user = insert(:user)
+
+    ["mute", "unmute"]
     |> Enum.each(fn(endpoint) ->
       conn = build_conn()
       |> assign(:user, user)