diff --git a/cpp/include/raft/distance/detail/euclidean.cuh b/cpp/include/raft/distance/detail/euclidean.cuh
index 1a2db63f5c..7c5fdb912c 100644
--- a/cpp/include/raft/distance/detail/euclidean.cuh
+++ b/cpp/include/raft/distance/detail/euclidean.cuh
@@ -34,6 +34,10 @@ struct L2ExpandedOp {
   __device__ AccT operator()(DataT& aNorm, const DataT& bNorm, DataT& accVal) const noexcept
   {
     AccT outVal = aNorm + bNorm - DataT(2.0) * accVal;
+    // outVal could be negative due to numerical instability, especially when
+    // calculating self distance.
+    // clamp to 0 to avoid potential NaN in sqrt
+    outVal = outVal * (outVal > DataT(0.0));
     return sqrt ? raft::sqrt(outVal) : outVal;
   }
 
@@ -122,7 +126,8 @@ void euclideanExpImpl(const DataT* x,
       for (int i = 0; i < KPolicy::AccRowsPerTh; ++i) {
 #pragma unroll
         for (int j = 0; j < KPolicy::AccColsPerTh; ++j) {
-          acc[i][j] = regxn[i] + regyn[j] - (DataT)2.0 * acc[i][j];
+          DataT val = regxn[i] + regyn[j] - (DataT)2.0 * acc[i][j];
+          acc[i][j] = val * (val > DataT(0.0));
         }
       }
       if (sqrt) {