The aim of the present study was to evaluate the effects on muscle stretchability, joint flexibility, muscle strength and endurance in construction workers of a 3-month period of a 10-min morning warming-up exercise (MWU), performed at the building site every working day. Thirty construction workers participated in the program. Seventeen construction workers at other building sites served as controls. Muscle stretchability, joint flexibility, muscle strength and endurance were measured before and after the program. Significant increase of thoracic and lower back mobility, increase of hamstring and thigh muscle stretchability were seen in the MWU group. A significant difference in back muscle endurance was found due to decreased endurance in the controls. Muscular strength was not influenced by the MWU. The results indicate that a short dose of morning warming-up exercise could be beneficial for increasing or maintaining joint and muscle flexibility and muscle endurance for workers exposed to manual material handling and strenuous working positions.