diff --git a/README.md b/README.md
new file mode 100644
index 0000000..256f223
--- /dev/null
+++ b/README.md
@@ -0,0 +1,19 @@
+# num
+
+Arbitrary sized numeric types for Rust.
+
+## Usage
+
+Add this to your `Cargo.toml`:
+
+```toml
+[dependencies.num]
+
+git = "https://github.com/rust-lang/num"
+```
+
+and this to your crate root:
+
+```rust
+extern crate num;
+```