diff --git a/Makefile b/Makefile
index b4e16da0..17dc99e0 100644
--- a/Makefile
+++ b/Makefile
@@ -57,11 +57,14 @@ else
 endif
 
 # Determine whether we can include CUDA and cuStateVec support. We build for
-# CUDA if (i) we find $NVCC or (ii) $CUDA_PATH is set. For cuStateVec, there's
-# no way to find the cuQuantum libraries other than by being told, so we rely
-# on the user or calling environment to set variable $CUQUANTUM_ROOT.
-
-ifneq (,$(shell which $(NVCC)))
+# CUDA if (i) we find nvidia-smi or (ii) $CUDA_PATH is set. For cuStateVec,
+# there's no way to find the cuQuantum libraries other than by being told, so
+# we rely on the user or calling environment to set variable $CUQUANTUM_ROOT.
+# (Testing for nvidia-smi is a more reliable way of checking that a system has
+# an NVIDIA GPU. Checking for nvcc may only tell you if the system can compile
+# CUDA code, not necessarily if it can run it.)
+
+ifneq (,$(shell command -v nvidia-smi > /dev/null 2>&1))
     # nvcc adds appropriate -I and -L flags, so nothing more is needed here.
     TARGETS += qsim-cuda
     TESTS += run-cuda-tests
diff --git a/pybind_interface/Makefile b/pybind_interface/Makefile
index 9bcc54b6..fa6cdfb8 100644
--- a/pybind_interface/Makefile
+++ b/pybind_interface/Makefile
@@ -54,9 +54,9 @@ PYBINDFLAGS_CUSTATEVEC = $(CUSTATEVECFLAGS) $(PYBINDFLAGS_CUDA)
 PYBINDFLAGS_HIP = -std=c++17 -Wall -shared -fPIC $(PYBIND_INCLUDES)
 
 # Check for nvcc to decide compilation mode.
-ifeq ($(shell which $(NVCC)),)
+ifeq ($(shell command -v $(NVCC) > /dev/null 2>&1),)
 # Check for hipcc to decide compilation mode.
-ifeq ($(shell which $(HIPCC)),)
+ifeq ($(shell command -v $(HIPCC) > /dev/null 2>&1),)
 pybind: pybind-cpu decide-cpu
 else
 pybind: pybind-hip decide-hip