Drivers in Eastwood and Kimberley are being advised to expect delays ahead of the sporting event this weekend.
The Moorgreen Duathlon is taking place around the borough on Sunday (October 11) and several roads will be affected.
The running and biking event, organised by Broxtowe Borough Council, will begin at Colliers Wood from 9am.
Roads affected in Newthorpe will be Engine Lane, Moorgreen and Willey Lane.
The event will then continue to Underwood, onto Alfreton Road, Mansfield Road and Sandhill Road.
It will then pass through Church Road in Greasley, before heading to Watnall.
Roads affected in Watnall will be Main Road, Stannier Way, Holly Road and Trough Road.
The finish time is yet to be confirmed.
For more information on the event, visit www.broxtowe.gov.uk or call Anna Smith-Clare on 01159 173 572.