diff --git a/rmw_microxrcedds_c/src/rmw_init.c b/rmw_microxrcedds_c/src/rmw_init.c
index 332d1eda..7bc966eb 100644
--- a/rmw_microxrcedds_c/src/rmw_init.c
+++ b/rmw_microxrcedds_c/src/rmw_init.c
@@ -35,6 +35,27 @@
 
 extern rmw_uxrce_transport_params_t rmw_uxrce_transport_default_params;
 
+static uint32_t
+generate_client_key(void)
+{
+  static uint32_t state = 0;
+  int64_t now = uxr_nanos();
+  uint32_t entropy = (uint32_t)(now ^ (now >> 32));
+  state ^= entropy;
+  if (state == 0) {
+    state = 0x1337BEEF;
+  }
+  uint32_t key;
+  do {
+    // 32-bit Marsaglia xorshift PRNG (zero dynamic memory allocation)
+    state ^= state << 13;
+    state ^= state >> 17;
+    state ^= state << 5;
+    key = state;
+  } while (key == 0);
+  return key;
+}
+
 rmw_ret_t
 rmw_init_options_init(
   rmw_init_options_t * init_options,
@@ -108,11 +129,7 @@ rmw_init_options_init(
   init_options->impl->transport_params.read_cb = rmw_uxrce_transport_default_params.read_cb;
 #endif /* if defined(RMW_UXRCE_TRANSPORT_SERIAL) */
 
-  srand(uxr_nanos());
-
-  do {
-    init_options->impl->transport_params.client_key = rand(); //NOLINT
-  } while (init_options->impl->transport_params.client_key == 0);
+  init_options->impl->transport_params.client_key = generate_client_key();
 
   return RMW_RET_OK;
 }
diff --git a/rmw_microxrcedds_c/test/test_rmw.cpp b/rmw_microxrcedds_c/test/test_rmw.cpp
index 1a8a954f..ca25ee0f 100644
--- a/rmw_microxrcedds_c/test/test_rmw.cpp
+++ b/rmw_microxrcedds_c/test/test_rmw.cpp
@@ -18,6 +18,7 @@
 #include <rmw/init_options.h>
 #include <rcutils/allocator.h>
 #include <rmw_microros/rmw_microros.h>
+#include <rmw_microros_internal/types.h>
 
 #include <ctime>
 
@@ -92,3 +93,28 @@ TEST(rmw_microxrcedds, sync_session)
   ASSERT_EQ(rmw_init_options_fini(&test_options), RMW_RET_OK);
   ASSERT_EQ(rmw_shutdown(&test_context), RMW_RET_OK);
 }
+
+/*
+ * Testing client_key generation in rmw_init_options_init. https://github.com/micro-ROS/rmw_microxrcedds/issues/324
+ */
+TEST(rmw_microxrcedds, client_key_generation)
+{
+  rmw_init_options_t options1 = rmw_get_zero_initialized_init_options();
+  rmw_init_options_t options2 = rmw_get_zero_initialized_init_options();
+
+  ASSERT_EQ(rmw_init_options_init(&options1, rcutils_get_default_allocator()), RMW_RET_OK);
+  ASSERT_EQ(rmw_init_options_init(&options2, rcutils_get_default_allocator()), RMW_RET_OK);
+
+  EXPECT_NE(options1.impl->transport_params.client_key, 0u);
+  EXPECT_NE(options2.impl->transport_params.client_key, 0u);
+  EXPECT_NE(options1.impl->transport_params.client_key, options2.impl->transport_params.client_key);
+
+  rmw_init_options_t options_copy = rmw_get_zero_initialized_init_options();
+  ASSERT_EQ(rmw_init_options_copy(&options1, &options_copy), RMW_RET_OK);
+  EXPECT_EQ(options_copy.impl->transport_params.client_key,
+    options1.impl->transport_params.client_key);
+
+  ASSERT_EQ(rmw_init_options_fini(&options_copy), RMW_RET_OK);
+  ASSERT_EQ(rmw_init_options_fini(&options1), RMW_RET_OK);
+  ASSERT_EQ(rmw_init_options_fini(&options2), RMW_RET_OK);
+}