diff --git a/src/doc/book/ffi.md b/src/doc/book/ffi.md
index d949bf33b6ee..c3896e4e9c55 100644
--- a/src/doc/book/ffi.md
+++ b/src/doc/book/ffi.md
@@ -517,8 +517,6 @@ The [`libc` crate on crates.io][libc] includes type aliases and function
 definitions for the C standard library in the `libc` module, and Rust links
 against `libc` and `libm` by default.
 
-[libc]: https://crates.io/crates/libc
-
 # The "nullable pointer optimization"
 
 Certain types are defined to not be `null`. This includes references (`&T`,