diff --git a/crypto/random_pool.c b/crypto/random_pool.c
index e7846901da0..d5bdcb56126 100644
--- a/crypto/random_pool.c
+++ b/crypto/random_pool.c
@@ -559,11 +559,17 @@ void up_randompool_initialize(void)
  *            together.
  *
  * Returned Value:
- *   None
+ *   On success, getrandom() returns the number of bytes that were copied
+ *   to the buffer buf.  This may be less than the number of bytes
+ *   requested via buflen if either GRND_RANDOM was specified in flags and
+ *   insufficient entropy was present in the random source or the system
+ *   call was interrupted by a signal.
+
+ *   On error, -1 is returned, and errno is set appropriately.
  *
  ****************************************************************************/
 
-void getrandom(FAR void *bytes, size_t nbytes, unsigned int flags)
+ssize_t getrandom(FAR void *bytes, size_t nbytes, unsigned int flags)
 {
   int ret;
 
@@ -572,5 +578,13 @@ void getrandom(FAR void *bytes, size_t nbytes, unsigned int flags)
     {
       rng_buf_internal(bytes, nbytes);
       nxsem_post(&g_rng.rd_sem);
+      ret = nbytes;
     }
+  else
+    {
+      set_errno(-ret);
+      ret = ERROR;
+    }
+
+  return ret;
 }
diff --git a/include/sys/random.h b/include/sys/random.h
index 4ac586176b9..d394e0f350c 100644
--- a/include/sys/random.h
+++ b/include/sys/random.h
@@ -48,8 +48,7 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
-/*
- * Flags for getrandom(2)
+/* Flags for getrandom(2)
  *
  * GRND_NONBLOCK  Don't block and return EAGAIN instead
  * GRND_RANDOM    No effect
@@ -84,11 +83,17 @@
  *            together.
  *
  * Returned Value:
- *   None
+ *   On success, getrandom() returns the number of bytes that were copied
+ *   to the buffer buf.  This may be less than the number of bytes
+ *   requested via buflen if either GRND_RANDOM was specified in flags and
+ *   insufficient entropy was present in the random source or the system
+ *   call was interrupted by a signal.
+ *
+ *   On error, -1 is returned, and errno is set appropriately.
  *
  ****************************************************************************/
 
-void getrandom(FAR void *bytes, size_t nbytes, unsigned int flags);
+ssize_t getrandom(FAR void *bytes, size_t nbytes, unsigned int flags);
 
 #endif /* CONFIG_CRYPTO_RANDOM_POOL */
 
diff --git a/syscall/syscall.csv b/syscall/syscall.csv
index 7d4a401a021..1bade984e07 100644
--- a/syscall/syscall.csv
+++ b/syscall/syscall.csv
@@ -35,7 +35,7 @@
 "getitimer","sys/time.h","!defined(CONFIG_DISABLE_POSIX_TIMERS)","int","int","FAR struct itimerval *"
 "getpeername","sys/socket.h","defined(CONFIG_NET)","int","int","FAR struct sockaddr *","FAR socklen_t *"
 "getpid","unistd.h","","pid_t"
-"getrandom","sys/random.h","defined(CONFIG_CRYPTO_RANDOM_POOL)","void","FAR void *","size_t","unsigned int"
+"getrandom","sys/random.h","defined(CONFIG_CRYPTO_RANDOM_POOL)","ssize_t","void","FAR void *","size_t","unsigned int"
 "getsockname","sys/socket.h","defined(CONFIG_NET)","int","int","FAR struct sockaddr *","FAR socklen_t *"
 "getsockopt","sys/socket.h","defined(CONFIG_NET)","int","int","int","int","FAR void *","FAR socklen_t *"
 "getuid","unistd.h","defined(CONFIG_SCHED_USER_IDENTITY)","uid_t"