diff --git a/ext/stackprof/stackprof.c b/ext/stackprof/stackprof.c
index 4cd865c2..b6c78a3f 100644
--- a/ext/stackprof/stackprof.c
+++ b/ext/stackprof/stackprof.c
@@ -107,6 +107,7 @@ static struct {
     size_t raw_samples_capa;
     size_t raw_sample_index;
 
+    struct timespec start_time;
     struct timestamp_t last_sample_at;
     sample_time_t *raw_sample_times;
     size_t raw_sample_times_len;
@@ -140,6 +141,7 @@ static VALUE sym_aggregate, sym_raw_sample_timestamps, sym_raw_timestamp_deltas,
 static VALUE sym_gc_samples, objtracer;
 static VALUE gc_hook;
 static VALUE rb_mStackProf;
+static VALUE sym_start_time_nsecs;
 
 static void stackprof_newobj_handler(VALUE, void*);
 static void stackprof_signal_handler(int sig, siginfo_t* sinfo, void* ucontext);
@@ -217,6 +219,8 @@ stackprof_start(int argc, VALUE *argv, VALUE self)
 	rb_raise(rb_eArgError, "unknown profiler mode");
     }
 
+    clock_gettime(CLOCK_REALTIME, &_stackprof.start_time);
+
     _stackprof.running = 1;
     _stackprof.raw = raw;
     _stackprof.aggregate = aggregate;
@@ -357,6 +361,7 @@ stackprof_results(int argc, VALUE *argv, VALUE self)
     results = rb_hash_new();
     rb_hash_aset(results, sym_version, DBL2NUM(1.2));
     rb_hash_aset(results, sym_mode, _stackprof.mode);
+    rb_hash_aset(results, sym_start_time_nsecs, LL2NUM(_stackprof.start_time.tv_sec * NANOSECONDS_IN_SECOND + _stackprof.start_time.tv_nsec));
     rb_hash_aset(results, sym_interval, _stackprof.interval);
     rb_hash_aset(results, sym_samples, SIZET2NUM(_stackprof.overall_samples));
     rb_hash_aset(results, sym_gc_samples, SIZET2NUM(_stackprof.during_gc));
@@ -946,6 +951,7 @@ Init_stackprof(void)
     S(state);
     S(marking);
     S(sweeping);
+    S(start_time_nsecs);
 #undef S
 
     /* Need to run this to warm the symbol table before we call this during GC */
diff --git a/test/test_stackprof.rb b/test/test_stackprof.rb
index b979e344..c6cf22bd 100644
--- a/test/test_stackprof.rb
+++ b/test/test_stackprof.rb
@@ -305,6 +305,14 @@ def test_min_max_interval
     end
   end
 
+  def test_start_time
+    before_run_realtime = Process.clock_gettime(Process::CLOCK_REALTIME, :nanosecond)
+
+    profile = StackProf.run{}
+    assert profile[:start_time_nsecs] != nil
+    assert_operator profile[:start_time_nsecs], :>, before_run_realtime
+  end
+
   def math
     250_000.times do
       2 ** 10