This paper describe the concept of maintenance of work ability (MWA) at workplaces and the contribution of occupational health services (OHS). Changing working life and its demands increase the need for MWA. The concept of MWA is approximately ten years old in Finland. It has attained large popularity in media and is a central trend in the promotion of well-being at workplaces. It has received wide approval in politics and labour market as one of the main topics of internal policies. The maintenance of work ability has become the main service of occupational health. The activities of MWA are increasing. It is considered profitable and it has many positive effects at workplaces, but has not yet been established properly as a part of everyday work processes. Occupational health services play a significant role in different phases of MWA process, but it should be more significant, especially in small workplaces. More trust, communication and collaboration are needed.