diff --git a/cpp/src/neighbors/detail/hnsw.hpp b/cpp/src/neighbors/detail/hnsw.hpp
index ce1e03264..b33c2fe01 100644
--- a/cpp/src/neighbors/detail/hnsw.hpp
+++ b/cpp/src/neighbors/detail/hnsw.hpp
@@ -114,7 +114,7 @@ template <typename T>
 void get_search_knn_results(hnswlib::HierarchicalNSW<typename hnsw_dist_t<T>::type> const* idx,
                             const T* query,
                             int k,
-                            uint64_t* indices,
+                            int64_t* indices,
                             float* distances)
 {
   auto result = idx->searchKnn(query, k);
@@ -132,7 +132,7 @@ void search(raft::resources const& res,
             const search_params& params,
             const index<T>& idx,
             raft::host_matrix_view<const T, int64_t, raft::row_major> queries,
-            raft::host_matrix_view<uint64_t, int64_t, raft::row_major> neighbors,
+            raft::host_matrix_view<int64_t, int64_t, raft::row_major> neighbors,
             raft::host_matrix_view<float, int64_t, raft::row_major> distances)
 {
   RAFT_EXPECTS(
diff --git a/cpp/src/neighbors/hnsw_c.cpp b/cpp/src/neighbors/hnsw_c.cpp
index a19875641..872a494fe 100644
--- a/cpp/src/neighbors/hnsw_c.cpp
+++ b/cpp/src/neighbors/hnsw_c.cpp
@@ -47,7 +47,7 @@ void _search(cuvsResources_t res,
   search_params.num_threads = params.numThreads;
 
   using queries_mdspan_type   = raft::host_matrix_view<T const, int64_t, raft::row_major>;
-  using neighbors_mdspan_type = raft::host_matrix_view<uint64_t, int64_t, raft::row_major>;
+  using neighbors_mdspan_type = raft::host_matrix_view<int64_t, int64_t, raft::row_major>;
   using distances_mdspan_type = raft::host_matrix_view<float, int64_t, raft::row_major>;
   auto queries_mds            = cuvs::core::from_dlpack<queries_mdspan_type>(queries_tensor);
   auto neighbors_mds          = cuvs::core::from_dlpack<neighbors_mdspan_type>(neighbors_tensor);