Bus passengers in the East Midlands are facing disruption as both drivers and engineers at Stagecoach take part in a one-day strike.
The RMT union says workers at Stagecoach want a better pay deal.
Stagecoach has issued a statement promising to operate "a reasonable level of service" during the walkout in Nottinghamshire and Derbyshire.
The workers voted by postal ballot to strike following an earlier decision to call off the action for more talks.
Management has offered driver rates of £7.50 an hour from next April and engineers a one-off rise of 9.2%.
Stagecoach said: "We are extremely disappointed that the deal agreed and recommended by the RMT Trade Union has been narrowly rejected.
"The fact is that this is the best deal we can offer and there is no more money available. "
The 400 coach workers at Stagecoach East Midlands are due to strike at depots in Chesterfield, Mansfield and Worksop.
The RMT negotiating committee had earlier recommended that workers accept the company pay offer.
For bus drivers the offer is a two-year package with a 5% rise to £7 an hour from 1 May, a further 2.9% from 30 October, and a 4.2% rise on 30 April next year to £7.50.