diff --git a/openssl-sys/Cargo.toml b/openssl-sys/Cargo.toml
index 3ce84e30..fe484a79 100644
--- a/openssl-sys/Cargo.toml
+++ b/openssl-sys/Cargo.toml
@@ -7,6 +7,7 @@ license = "MIT"
 description = "FFI bindings to OpenSSL"
 repository = "https://github.com/sfackler/rust-openssl"
 documentation = "https://docs.rs/openssl-sys/0.9.6/openssl_sys"
+categories = ["cryptography", "external-ffi-bindings"]
 links = "openssl"
 build = "build.rs"
 
diff --git a/openssl/Cargo.toml b/openssl/Cargo.toml
index a4baa79d..d1893fe8 100644
--- a/openssl/Cargo.toml
+++ b/openssl/Cargo.toml
@@ -8,6 +8,7 @@ repository = "https://github.com/sfackler/rust-openssl"
 documentation = "https://docs.rs/openssl/0.9.6/openssl"
 readme = "../README.md"
 keywords = ["crypto", "tls", "ssl", "dtls"]
+categories = ["cryptography", "api-bindings"]
 build = "build.rs"
 exclude = ["test/*"]