diff --git a/libutils/SystemClock.cpp b/libutils/SystemClock.cpp
index 73ec1be..9c71141 100644
--- a/libutils/SystemClock.cpp
+++ b/libutils/SystemClock.cpp
@@ -39,8 +39,15 @@
  */
 int64_t uptimeMillis()
 {
-    int64_t when = systemTime(SYSTEM_TIME_MONOTONIC);
-    return (int64_t) nanoseconds_to_milliseconds(when);
+    return nanoseconds_to_milliseconds(uptimeNanos());
+}
+
+/*
+ * public static native long uptimeNanos();
+ */
+int64_t uptimeNanos()
+{
+    return systemTime(SYSTEM_TIME_MONOTONIC);
 }
 
 /*
diff --git a/libutils/SystemClock_test.cpp b/libutils/SystemClock_test.cpp
index 5ad060b..7449dad 100644
--- a/libutils/SystemClock_test.cpp
+++ b/libutils/SystemClock_test.cpp
@@ -29,16 +29,24 @@
 
 TEST(SystemClock, SystemClock) {
     auto startUptimeMs = android::uptimeMillis();
+    auto startUptimeNs = android::uptimeNanos();
     auto startRealtimeMs = android::elapsedRealtime();
     auto startRealtimeNs = android::elapsedRealtimeNano();
 
     ASSERT_GT(startUptimeMs, 0)
             << "uptimeMillis() reported an impossible uptime";
+    ASSERT_GT(startUptimeNs, 0)
+            << "uptimeNanos() reported an impossible uptime";
     ASSERT_GE(startRealtimeMs, startUptimeMs)
             << "elapsedRealtime() thinks we've suspended for negative time";
-    ASSERT_GE(startRealtimeNs, startUptimeMs * MS_IN_NS)
+    ASSERT_GE(startRealtimeNs, startUptimeNs)
             << "elapsedRealtimeNano() thinks we've suspended for negative time";
 
+    ASSERT_GE(startUptimeNs, startUptimeMs * MS_IN_NS)
+            << "uptimeMillis() and uptimeNanos() are inconsistent";
+    ASSERT_LT(startUptimeNs, (startUptimeMs + SLACK_MS) * MS_IN_NS)
+            << "uptimeMillis() and uptimeNanos() are inconsistent";
+
     ASSERT_GE(startRealtimeNs, startRealtimeMs * MS_IN_NS)
             << "elapsedRealtime() and elapsedRealtimeNano() are inconsistent";
     ASSERT_LT(startRealtimeNs, (startRealtimeMs + SLACK_MS) * MS_IN_NS)
@@ -51,6 +59,7 @@
     ASSERT_EQ(nanosleepErr, 0) << "nanosleep() failed: " << strerror(errno);
 
     auto endUptimeMs = android::uptimeMillis();
+    auto endUptimeNs = android::uptimeNanos();
     auto endRealtimeMs = android::elapsedRealtime();
     auto endRealtimeNs = android::elapsedRealtimeNano();
 
@@ -58,6 +67,10 @@
             << "uptimeMillis() advanced too little after nanosleep()";
     EXPECT_LT(endUptimeMs - startUptimeMs, SLEEP_MS + SLACK_MS)
             << "uptimeMillis() advanced too much after nanosleep()";
+    EXPECT_GE(endUptimeNs - startUptimeNs, SLEEP_NS)
+            << "uptimeNanos() advanced too little after nanosleep()";
+    EXPECT_LT(endUptimeNs - startUptimeNs, SLEEP_NS + SLACK_NS)
+            << "uptimeNanos() advanced too much after nanosleep()";
     EXPECT_GE(endRealtimeMs - startRealtimeMs, SLEEP_MS)
             << "elapsedRealtime() advanced too little after nanosleep()";
     EXPECT_LT(endRealtimeMs - startRealtimeMs, SLEEP_MS + SLACK_MS)
@@ -67,6 +80,11 @@
     EXPECT_LT(endRealtimeNs - startRealtimeNs, SLEEP_NS + SLACK_NS)
             << "elapsedRealtimeNano() advanced too much after nanosleep()";
 
+    EXPECT_GE(endUptimeNs, endUptimeMs * MS_IN_NS)
+            << "uptimeMillis() and uptimeNanos() are inconsistent after nanosleep()";
+    EXPECT_LT(endUptimeNs, (endUptimeMs + SLACK_MS) * MS_IN_NS)
+            << "uptimeMillis() and uptimeNanos() are inconsistent after nanosleep()";
+
     EXPECT_GE(endRealtimeNs, endRealtimeMs * MS_IN_NS)
             << "elapsedRealtime() and elapsedRealtimeNano() are inconsistent after nanosleep()";
     EXPECT_LT(endRealtimeNs, (endRealtimeMs + SLACK_MS) * MS_IN_NS)
diff --git a/libutils/include/utils/SystemClock.h b/libutils/include/utils/SystemClock.h
index f816fba..892104c 100644
--- a/libutils/include/utils/SystemClock.h
+++ b/libutils/include/utils/SystemClock.h
@@ -23,6 +23,7 @@
 namespace android {
 
 int64_t uptimeMillis();
+int64_t uptimeNanos();
 int64_t elapsedRealtime();
 int64_t elapsedRealtimeNano();