diff --git a/scrapy/core/engine.py b/scrapy/core/engine.py
index 957847af6..0524c74f2 100644
--- a/scrapy/core/engine.py
+++ b/scrapy/core/engine.py
@@ -93,7 +93,7 @@ class ExecutionEngine(object):
         if not self.running:
             self.control_reactor = control_reactor
             reactor.callLater(0, self._mainloop)
-            self.start_time = datetime.now()
+            self.start_time = datetime.utcnow()
             signals.send_catch_log(signal=signals.engine_started, sender=self.__class__)
             self.addtask(self._mainloop, 5.0)
             for tsk, interval, now in self.tasks:
@@ -328,7 +328,7 @@ class ExecutionEngine(object):
         s = "Execution engine status\n\n"
 
         global_tests = [
-            "datetime.now()-self.start_time", 
+            "datetime.utcnow()-self.start_time", 
             "self.is_idle()", 
             "self.scheduler.is_idle()",
             "len(self.scheduler.pending_requests)",
diff --git a/scrapy/stats/collector/mysql.py b/scrapy/stats/collector/mysql.py
index bf4e3fbc4..0849743dd 100644
--- a/scrapy/stats/collector/mysql.py
+++ b/scrapy/stats/collector/mysql.py
@@ -18,7 +18,7 @@ class MysqlStatsCollector(StatsCollector):
         
     def close_domain(self, domain, reason):
         if self._mysql_conn:
-            stored = datetime.now()
+            stored = datetime.utcnow()
             datas = pickle.dumps(self._stats[domain])
             table = 'domain_data_history'
 
diff --git a/scrapy/stats/collector/simpledb.py b/scrapy/stats/collector/simpledb.py
index cfe87bb84..82e4040c8 100644
--- a/scrapy/stats/collector/simpledb.py
+++ b/scrapy/stats/collector/simpledb.py
@@ -35,7 +35,7 @@ class SimpledbStatsCollector(StatsCollector):
         super(SimpledbStatsCollector, self).close_domain(domain, reason)
 
     def _persist_to_sdb(self, domain, stats):
-        ts = datetime.now().isoformat()
+        ts = datetime.utcnow().isoformat()
         sdb_item_id = "%s_%s" % (domain, ts)
         sdb_item = dict([(k, self._to_sdb_value(v)) for k, v in stats.iteritems()])
         sdb_item['domain'] = domain
diff --git a/scrapy/stats/corestats.py b/scrapy/stats/corestats.py
index 0ebfc230f..f70a4aa8e 100644
--- a/scrapy/stats/corestats.py
+++ b/scrapy/stats/corestats.py
@@ -29,12 +29,12 @@ class CoreStats(object):
         dispatcher.connect(self.item_dropped, signal=signals.item_dropped)
 
     def stats_domain_opened(self, domain):
-        stats.set_value('start_time', datetime.datetime.now(), domain=domain)
+        stats.set_value('start_time', datetime.datetime.utcnow(), domain=domain)
         stats.set_value('envinfo/host', stats.get_value('envinfo/host'), domain=domain)
         stats.inc_value('domain_count/opened')
 
     def stats_domain_closing(self, domain, reason):
-        stats.set_value('finish_time', datetime.datetime.now(), domain=domain)
+        stats.set_value('finish_time', datetime.datetime.utcnow(), domain=domain)
         stats.set_value('finish_status', 'OK' if reason == 'finished' else reason, domain=domain)
         stats.inc_value('domain_count/%s' % reason, domain=domain)