The Work ability of ageing work force is a matter of major concern in many countries. The aim of this study was to examine the relationship between perceived work ability and health-related quality of life (HRQoL), and to investigate their associations with age, physical activity and physical fitness in middle-aged men working in blue-collar occupations. The study population consisted of 196 middle-aged (aged 40-60 years) men (construction and industrial work) attending occupationally orientated early medical rehabilitation. They were mostly healthy having only symptoms of musculoskeletal or psychological strain. Perceived work ability was assessed with the work ability index (WAI) and HRQoL with the Rand, 36-item health survey (Rand-36). Information on physical activity was obtained with a structured questionnaire. Cardiorespiratory fitness was estimated with a submaximal exercise test on a cycle-ergometer. The WAI was significantly (p<0.001) associated with the total score of Rand-36, and with all its domains. Age, physical activity and cardiorespiratory fitness were neither associated with the WAI, nor did physical activity predict any of the dimensions of Rand-36. Cardiorespiratory fitness was associated with the physical functioning dimension of the Rand-36 whilst age was positively associated with the dimensions of the energy, emotional well being and social functioning of the Rand-36. The present study on middle-aged men showed a close relationship between perceived work ability and the HRQoL. It is suggested that the promotion of work ability may have beneficial effects on quality of life.