diff --git a/src/runtime/current_thread/runtime.rs b/src/runtime/current_thread/runtime.rs
index 262cb1e72d8..6bb2b076768 100644
--- a/src/runtime/current_thread/runtime.rs
+++ b/src/runtime/current_thread/runtime.rs
@@ -92,6 +92,10 @@ impl Error for RunError {
     fn description(&self) -> &str {
         self.inner.description()
     }
+
+    // FIXME(taiki-e): When the minimum support version of tokio reaches Rust 1.30,
+    // replace this with Error::source.
+    #[allow(deprecated)]
     fn cause(&self) -> Option<&Error> {
         self.inner.cause()
     }
diff --git a/tokio-timer/src/throttle.rs b/tokio-timer/src/throttle.rs
index c1da76bbf89..12e8895764a 100644
--- a/tokio-timer/src/throttle.rs
+++ b/tokio-timer/src/throttle.rs
@@ -161,6 +161,9 @@ impl<T: StdError + 'static> StdError for ThrottleError<T> {
         }
     }
 
+    // FIXME(taiki-e): When the minimum support version of tokio reaches Rust 1.30,
+    // replace this with Error::source.
+    #[allow(deprecated)]
     fn cause(&self) -> Option<&StdError> {
         match self.0 {
             Either::A(ref err) => Some(err),