diff --git a/README.md b/README.md
index a2516951..a305373e 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,11 @@ This project is developed and maintained by the [Cortex-M team][team].
 
 # [Documentation](https://docs.rs/cortex-m-rt)
 
+# Minimum Supported Rust Version (MSRV)
+
+This crate is guaranteed to compile on stable Rust 1.39.0 and up. It *might*
+compile with older versions but that may change in any new patch release.
+
 # License
 
 Licensed under either of