diff --git a/StopWatch.cpp b/StopWatch.cpp
index 77d539d..046a943 100644
--- a/StopWatch.cpp
+++ b/StopWatch.cpp
@@ -64,21 +64,16 @@ CStopWatch::~CStopWatch()
 
 unsigned long CStopWatch::start()
 {
-	::gettimeofday(&m_start, NULL);
-
-	return m_start.tv_usec;
+	::clock_gettime(CLOCK_MONOTONIC, &m_start);
+	return m_start.tv_sec;
 }
 
 unsigned int CStopWatch::elapsed()
 {
-	struct timeval now;
-	::gettimeofday(&now, NULL);
-
-	unsigned int elapsed = (now.tv_sec - m_start.tv_sec) * 1000U;
-	elapsed += now.tv_usec / 1000U;
-	elapsed -= m_start.tv_usec / 1000U;
-
-	return elapsed;
+	struct timespec now;
+	::clock_gettime(CLOCK_MONOTONIC, &now);
+	int offset = ((now.tv_sec - m_start.tv_sec) * 1000000000UL + now.tv_nsec - m_start.tv_nsec ) / 1000000UL;
+	return (unsigned int)offset;
 }
 
 #endif
diff --git a/StopWatch.h b/StopWatch.h
index 811047e..a1e2bf8 100644
--- a/StopWatch.h
+++ b/StopWatch.h
@@ -39,7 +39,7 @@ private:
 	LARGE_INTEGER  m_frequency;
 	LARGE_INTEGER  m_start;
 #else
-	struct timeval m_start;
+	struct timespec m_start;
 #endif
 };