diff --git a/README.md b/README.md
index 5070675..d7d56f4 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,7 @@ SCT.rs is a certificate transparency SCT verifier in rust.  It
 It uses [*ring*](https://github.com/briansmith/ring) for cryptography.
 
 [![Build Status](https://travis-ci.org/ctz/sct.rs.svg?branch=master)](https://travis-ci.org/ctz/sct.rs)
+[![Coverage Status](https://coveralls.io/repos/github/ctz/sct.rs/badge.svg?branch=master)](https://coveralls.io/github/ctz/sct.rs?branch=master)
 [![Documentation](https://docs.rs/sct/badge.svg)](https://docs.rs/sct/)
 [![Crates.io](https://img.shields.io/crates/v/sct.svg)](https://crates.io/crates/sct)