Physical activity has considerable health-enhancing potential. It will be realized, however, only if large number of people participate in adequate activity. This summary report describes the main results of four studies aimed to find out whether physically active commuting to work (PACW) meets the requirements of health and fitness enhancing activity. Three successive mail inquiries (N = 2014) indicated that PACW provided habitual exercise to one-third of employed urban population, and that more than one-fifth expressed willingness and being able to increase PACW. A randomized controlled trial on 68 inactive middle-aged men and women revealed that PACW (1 h daily for 10 wk) increased VO2max by 4.5% (P = 0.02), maximal treadmill time by 10.3% (P = 0.0007), and HDL cholesterol by 5% (P = 0.06). A demonstration project in a large industrial plant showed that PACW can be successfully promoted by low cost measures. In conclusion, these studies suggest that PACW may offer substantial potential as health and fitness enhancing measure provided that it can be practiced safely.