diff --git a/openssl-sys/Cargo.toml b/openssl-sys/Cargo.toml
index b7db70ab..5d1783df 100644
--- a/openssl-sys/Cargo.toml
+++ b/openssl-sys/Cargo.toml
@@ -9,7 +9,6 @@ repository = "https://github.com/sfackler/rust-openssl"
 readme = "README.md"
 categories = ["cryptography", "external-ffi-bindings"]
 links = "openssl"
-build = "build.rs"
 
 [dependencies]
 libc = "0.2"
diff --git a/openssl/Cargo.toml b/openssl/Cargo.toml
index 92302043..cbfab25e 100644
--- a/openssl/Cargo.toml
+++ b/openssl/Cargo.toml
@@ -8,7 +8,6 @@ repository = "https://github.com/sfackler/rust-openssl"
 readme = "README.md"
 keywords = ["crypto", "tls", "ssl", "dtls"]
 categories = ["cryptography", "api-bindings"]
-build = "build.rs"
 
 # these are deprecated and don't do anything anymore
 [features]
diff --git a/systest/Cargo.toml b/systest/Cargo.toml
index 3997bf35..e9d7af64 100644
--- a/systest/Cargo.toml
+++ b/systest/Cargo.toml
@@ -2,7 +2,6 @@
 name = "systest"
 version = "0.1.0"
 authors = ["Alex Crichton <alex@alexcrichton.com>"]
-build = "build.rs"
 
 [dependencies]
 libc = "0.2"