diff --git a/imhamt/src/hamt.rs b/imhamt/src/hamt.rs
index cb99d798d..632a7b895 100644
--- a/imhamt/src/hamt.rs
+++ b/imhamt/src/hamt.rs
@@ -4,6 +4,7 @@ use super::node::{
     update_rec, Entry, LookupRet, Node, NodeIter,
 };
 pub use super::operation::{InsertError, RemoveError, ReplaceError, UpdateError};
+use std::borrow::Borrow;
 use std::iter::FromIterator;
 use std::marker::PhantomData;
 use std::mem::swap;
@@ -177,8 +178,12 @@ impl<H: Hasher + Default, K: Eq + Hash + Clone, V: Clone> Hamt<H, K, V> {
 
 impl<H: Hasher + Default, K: Hash + Eq, V> Hamt<H, K, V> {
     /// Try to get the element related to key K
-    pub fn lookup(&self, k: &K) -> Option<&V> {
-        let h = HashedKey::compute(self.hasher, &k);
+    pub fn lookup<Q>(&self, k: &Q) -> Option<&V>
+    where
+        K: Borrow<Q>,
+        Q: Hash + PartialEq,
+    {
+        let h = HashedKey::compute(self.hasher, k.borrow());
         let mut n = &self.root;
         let mut lvl = 0;
         loop {
@@ -193,7 +198,10 @@ impl<H: Hasher + Default, K: Hash + Eq, V> Hamt<H, K, V> {
         }
     }
     /// Check if the key is contained into the HAMT
-    pub fn contains_key(&self, k: &K) -> bool {
+    pub fn contains_key<Q: Hash + PartialEq>(&self, k: &Q) -> bool
+    where
+        K: Borrow<Q>,
+    {
         self.lookup(k).map_or_else(|| false, |_| true)
     }
     pub fn iter(&self) -> HamtIter<K, V> {
diff --git a/imhamt/src/node/reference.rs b/imhamt/src/node/reference.rs
index 6a4ca6201..8ec8e6db6 100644
--- a/imhamt/src/node/reference.rs
+++ b/imhamt/src/node/reference.rs
@@ -3,6 +3,7 @@ use super::super::hash::{HashedKey, LevelIndex};
 use super::super::helper;
 use super::super::operation::*;
 use super::super::sharedref::SharedRef;
+use std::borrow::Borrow;
 
 use std::slice;
 
@@ -305,11 +306,11 @@ pub enum LookupRet<'a, K, V> {
     ContinueIn(&'a Node<K, V>),
 }
 
-pub fn lookup_one<'a, K: PartialEq, V>(
+pub fn lookup_one<'a, Q: PartialEq, K: PartialEq + Borrow<Q>, V>(
     node: &'a Node<K, V>,
     h: &HashedKey,
     lvl: usize,
-    k: &K,
+    k: &Q,
 ) -> LookupRet<'a, K, V> {
     let level_hash = h.level_index(lvl);
     let idx = node.bitmap.get_index_sparse(level_hash);
@@ -318,7 +319,7 @@ pub fn lookup_one<'a, K: PartialEq, V>(
     } else {
         match &(node.get_child(idx)).as_ref() {
             Entry::Leaf(lh, lk, lv) => {
-                if lh == h && lk == k {
+                if lh == h && lk.borrow() == k {
                     LookupRet::Found(lv)
                 } else {
                     LookupRet::NotFound
@@ -328,7 +329,7 @@ pub fn lookup_one<'a, K: PartialEq, V>(
                 if lh != h {
                     LookupRet::NotFound
                 } else {
-                    match col.0.iter().find(|(lk, _)| lk == k) {
+                    match col.0.iter().find(|(lk, _)| lk.borrow() == k) {
                         None => LookupRet::NotFound,
                         Some(lkv) => LookupRet::Found(&lkv.1),
                     }