diff --git a/src/channel.rs b/src/channel.rs
index 85060e52b..e9e023867 100644
--- a/src/channel.rs
+++ b/src/channel.rs
@@ -23,6 +23,7 @@ use reactor::{Handle, PollEvented};
 /// This type is created by the [`channel`] function.
 ///
 /// [`channel`]: fn.channel.html
+#[must_use = "sinks do nothing unless polled"]
 pub struct Sender<T> {
     tx: channel::Sender<T>,
 }
diff --git a/src/net/udp/frame.rs b/src/net/udp/frame.rs
index 1bb5deed6..5ae41b738 100644
--- a/src/net/udp/frame.rs
+++ b/src/net/udp/frame.rs
@@ -55,6 +55,7 @@ pub trait UdpCodec {
 ///
 /// You can acquire a `UdpFramed` instance by using the `UdpSocket::framed`
 /// adapter.
+#[must_use = "sinks do nothing unless polled"]
 pub struct UdpFramed<C> {
     socket: UdpSocket,
     codec: C,