diff --git a/time.c b/time.c
index 04f99f2..7ae7230 100644
--- a/time.c
+++ b/time.c
@@ -16,6 +16,10 @@
 #include "ruby/encoding.h"
 #include "internal.h"
 
+#ifdef OSX
+#include <kern/clock.h>
+#endif
+
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
 #endif
@@ -3152,6 +3156,43 @@ time_s_mktime(int argc, VALUE *argv, VALUE klass)
     return time_utc_or_local(argc, argv, FALSE, klass);
 }
 
+/* call-seq:
+ *   Time.monotonic
+ *
+ * Returns monotonic counter if available on system. Will throw exception 
+ * if fails. Currently supports Windows (from 2000), OS/X and any *nix with 
+ * clock_gettime. Time is returned in nanoseconds. 
+ *
+ *    Time.monotonic   #=> 15898248961398385
+ */
+static VALUE
+time_s_monotonic(VALUE klass) {
+#ifdef WIN32 
+    LARGE_INTEGER ts, freq;
+    QueryPerformanceFrequency(&freq);
+    QueryPerformanceCounter(&ts);
+    return INT64toNUM((ts.QuadPart * 1000000000LL) / freq.QuadPart);
+#elif defined OSX
+    uint64_t abs,ts;
+    abs =  mach_absolute_time();
+    absolutetime_to_nanoseconds(abs, &ts);
+    return INT64toNUM(ts);
+#else
+#ifdef HAVE_CLOCK_GETTIME
+    struct timespec ts;
+#ifdef CLOCK_MONOTONIC_RAW
+    if (!clock_gettime(CLOCK_MONOTONIC_RAW, &ts)) 
+	return INT64toNUM(((long long unsigned) ts.tv_sec*1000000000) + (long long unsigned) ts.tv_nsec);
+#elif defined CLOCK_MONOTONIC
+    if (!clock_gettime(CLOCK_MONOTONIC, &ts))
+	return INT64toNUM(((long long unsigned) ts.tv_sec*1000000000) + (long long unsigned) ts.tv_nsec);
+    rb_raise(rb_eRuntimeError, "clock_gettime() failed");
+#endif
+#endif
+#endif
+    rb_raise(rb_eNotImpError, "No monotonic clock found");
+}
+
 /*
  *  call-seq:
  *     time.to_i   -> int
@@ -4973,6 +5014,7 @@ Init_Time(void)
     rb_define_singleton_method(rb_cTime, "gm", time_s_mkutc, -1);
     rb_define_singleton_method(rb_cTime, "local", time_s_mktime, -1);
     rb_define_singleton_method(rb_cTime, "mktime", time_s_mktime, -1);
+    rb_define_singleton_method(rb_cTime, "monotonic", time_s_monotonic, -1);
 
     rb_define_method(rb_cTime, "to_i", time_to_i, 0);
     rb_define_method(rb_cTime, "to_f", time_to_f, 0);