diff --git a/cub/cub/block/specializations/block_reduce_warp_reductions.cuh b/cub/cub/block/specializations/block_reduce_warp_reductions.cuh
index 85eacd787a3..2dfa526771f 100644
--- a/cub/cub/block/specializations/block_reduce_warp_reductions.cuh
+++ b/cub/cub/block/specializations/block_reduce_warp_reductions.cuh
@@ -50,8 +50,6 @@
 
 #include <cuda/ptx>
 
-CUB_NAMESPACE_BEGIN
-
 CUB_NAMESPACE_BEGIN
 namespace detail
 {
diff --git a/cub/cub/block/specializations/block_scan_warp_scans.cuh b/cub/cub/block/specializations/block_scan_warp_scans.cuh
index b2009e7ae76..d034d2838ea 100644
--- a/cub/cub/block/specializations/block_scan_warp_scans.cuh
+++ b/cub/cub/block/specializations/block_scan_warp_scans.cuh
@@ -49,8 +49,6 @@
 
 #include <cuda/ptx>
 
-CUB_NAMESPACE_BEGIN
-
 CUB_NAMESPACE_BEGIN
 namespace detail
 {
diff --git a/cub/cub/warp/specializations/warp_reduce_smem.cuh b/cub/cub/warp/specializations/warp_reduce_smem.cuh
index 3041c98be36..ade195ee6cb 100644
--- a/cub/cub/warp/specializations/warp_reduce_smem.cuh
+++ b/cub/cub/warp/specializations/warp_reduce_smem.cuh
@@ -51,8 +51,6 @@
 
 #include <cuda/ptx>
 
-CUB_NAMESPACE_BEGIN
-
 CUB_NAMESPACE_BEGIN
 namespace detail
 {
diff --git a/cub/cub/warp/specializations/warp_scan_shfl.cuh b/cub/cub/warp/specializations/warp_scan_shfl.cuh
index 624034699e2..402b476c4e4 100644
--- a/cub/cub/warp/specializations/warp_scan_shfl.cuh
+++ b/cub/cub/warp/specializations/warp_scan_shfl.cuh
@@ -50,8 +50,6 @@
 
 #include <cuda/ptx>
 
-CUB_NAMESPACE_BEGIN
-
 CUB_NAMESPACE_BEGIN
 namespace detail
 {
diff --git a/cub/cub/warp/specializations/warp_scan_smem.cuh b/cub/cub/warp/specializations/warp_scan_smem.cuh
index c1bd74bb2ca..090f0f96cb5 100644
--- a/cub/cub/warp/specializations/warp_scan_smem.cuh
+++ b/cub/cub/warp/specializations/warp_scan_smem.cuh
@@ -51,8 +51,6 @@
 
 #include <cuda/ptx>
 
-CUB_NAMESPACE_BEGIN
-
 CUB_NAMESPACE_BEGIN
 namespace detail
 {