diff --git a/Cargo.toml b/Cargo.toml
index 8851bda..fbad54a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,7 +13,7 @@ description = "A binary serialization / deserialization strategy and implementat
 [dependencies]
 rustc-serialize = { version = "0.3.*", optional = true }
 byteorder = "0.5.*"
-num = "0.1.*"
+num = { version = "0.1.*", default-features = false }
 serde = { version = "0.7.*", optional = true }
 
 [dev-dependencies]