diff --git a/README.md b/README.md
index 6e46fa4..0ff3431 100644
--- a/README.md
+++ b/README.md
@@ -5,4 +5,6 @@
 
 This code reads and writes the [old PDB format](https://www.wwpdb.org/documentation/file-format-content/format33/v3.3.html).
 
+See [the documentation](https://old-pdb.readthedocs.io/en/latest/?badge=latest) for more information.
+
 Development of this code was greatly helped by [the Chimera documentation](https://www.cgl.ucsf.edu/chimera/docs/UsersGuide/tutorials/pdbintro.html).