diff --git a/openssl/src/dh/mod.rs b/openssl/src/dh/mod.rs
index 4dc17158..78dcb778 100644
--- a/openssl/src/dh/mod.rs
+++ b/openssl/src/dh/mod.rs
@@ -3,6 +3,11 @@ use error::ErrorStack;
 use bio::MemBioSlice;
 use std::ptr;
 
+#[cfg(feature = "dh_from_params")]
+use bn::BigNum;
+#[cfg(feature = "dh_from_params")]
+use std::mem;
+
 pub struct DH(*mut ffi::DH);
 
 impl DH {