diff --git a/README.md b/README.md
index 8eba63c..b04f9e7 100644
--- a/README.md
+++ b/README.md
@@ -16,6 +16,7 @@ Install diff-edit directly using pip:
 Or install from source:
 
     git clone https://github.com/ahamilton/diff-edit
+    pip install --upgrade pip  # A recent version of pip is needed.
     pip install ./diff-edit
 
 Then to run: