diff --git a/pyproject.toml b/pyproject.toml
index 860741e..b48c3f7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -7,7 +7,7 @@ dependencies = [
 ]
 description = "Python implementation of Library of Congress EDTF (Extended Date Time Format) specification"
 requires-python = ">=3.8"
-readme = {file = "README.txt", content-type = "text/markdown"}
+readme = {file = "README.md", content-type = "text/markdown"}
 authors = [
     { name = "The Interaction Consortium", email = "studio@interaction.net.au"},
     { name = "Alastair Weakley"},