diff --git a/src/cursor.rs b/src/cursor.rs
index 0feb3f1..8899d3f 100644
--- a/src/cursor.rs
+++ b/src/cursor.rs
@@ -218,7 +218,7 @@ unsafe fn slice_to_val(slice: Option<&[u8]>) -> ffi::MDB_val {
 unsafe fn val_to_slice<'a>(val: ffi::MDB_val) -> &'a [u8] {
     mem::transmute(raw::Slice {
         data: val.mv_data as *const u8,
-        len: val.mv_size as uint
+        len: val.mv_size as usize
     })
 }
 
diff --git a/src/lib.rs b/src/lib.rs
index 90aa80c..f10c6f0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -5,6 +5,7 @@
 //! general, the API is very similar to the LMDB [C-API](http://symas.com/mdb/doc/).
 
 #![feature(unsafe_destructor)]
+#![allow(unstable)]
 
 #[macro_use] extern crate log;
 extern crate libc;
diff --git a/src/transaction.rs b/src/transaction.rs
index e202b98..092549f 100644
--- a/src/transaction.rs
+++ b/src/transaction.rs
@@ -80,7 +80,7 @@ pub trait TransactionExt<'env> : Transaction<'env> + Sized {
                 ffi::MDB_SUCCESS => {
                     Ok(mem::transmute(raw::Slice {
                         data: data_val.mv_data as *const u8,
-                        len: data_val.mv_size as uint
+                        len: data_val.mv_size as usize
                     }))
                 },
                 err_code => Err(LmdbError::from_err_code(err_code)),
@@ -317,7 +317,7 @@ impl <'env> RwTransaction<'env> {
             let slice: &'txn mut [u8] =
                 mem::transmute(raw::Slice {
                     data: data_val.mv_data as *const u8,
-                    len: data_val.mv_size as uint
+                    len: data_val.mv_size as usize
                 });
             Ok(BufWriter::new(slice))
         }
@@ -534,7 +534,7 @@ mod test {
         let dir = io::TempDir::new("test").unwrap();
         let env: Arc<Environment> = Arc::new(Environment::new().open(dir.path(), io::USER_RWX).unwrap());
 
-        let n = 10u; // Number of concurrent readers
+        let n = 10us; // Number of concurrent readers
         let barrier = Arc::new(Barrier::new(n + 1));
         let mut futures: Vec<Future<bool>> = Vec::with_capacity(n);
 
@@ -576,7 +576,7 @@ mod test {
         let dir = io::TempDir::new("test").unwrap();
         let env = Arc::new(Environment::new().open(dir.path(), io::USER_RWX).unwrap());
 
-        let n = 10u; // Number of concurrent writers
+        let n = 10us; // Number of concurrent writers
         let mut futures: Vec<Future<bool>> = Vec::with_capacity(n);
 
         let key = "key";
@@ -620,7 +620,7 @@ mod test {
         XorShiftRng::new_unseeded().shuffle(keys.as_mut_slice());
 
         b.iter(|| {
-            let mut i = 0u;
+            let mut i = 0us;
             for key in keys.iter() {
                 i = i + txn.get(db, key.as_bytes()).unwrap().len();
             }