Around 140 top cyclists are taking part in the Chorley Prix.
The race, which starts the 2016 British Elite Road Race Series, follows a five-lap 116-mile route through Chorley and surrounding areas, including Rivington, Withnell, Brinscall and Buckshaw Village.
The second annual Chorley race has attracted hundreds of spectators
Decorated bicycles have already appeared along the route as cycling fans show their support and people are being encouraged to take flags and banners as they watch the race.
Last year’s winner Ian Bibby, from Preston, is defending his title and multi-Olympic gold medal winner Ed Clancy has returned to Chorley.
There is a cycle village on Park Road with activities and people can have their bicycles checked by “bike doctors”.
Rolling road closures are in place as cyclists go past, with Park Road and part of Queens Road closed all day. Southport Road will be closed for the last lap and one side of Sheep House Lane and Rivington Road will be closed to west-bound traffic for the day.