Labour costs represent the major portion of the total cost in many industries and activities. This investigation examines a four-day workweek (compared with the current five-day week schedule) for maintenance operations in the Power Holding Company of Nigeria (PHCN). The aim is to reduce maintenance labour-costs, while satisfying increasing demands for higher effectiveness. Changing from the five to a four-day workweek for maintenance personnel at the Afam power-station is predicted to produce savings of 10% of maintenance labour cost without any loss of output or quality of service. (c) 2007 Elsevier Ltd. All rights reserved.