Regular male passengers commuting on the Nynäshamn-Stockholm line participated in a four day investigation aimed at studying the stress, which arises from day-to-day commuting from a surburban home to a central-city job. All subjects rode a morning train; one group boarded the train at its first stop, and the other "midway "on its trip. The time of travelling was 79 and 43 min, respectively. On each day the subjects made quantitative reports concerning the travelling conditions on the train, and on the third day urine specimens from each passenger were also collected and analyzed for adrenaline and noradrenaline. The mean number of passengers/car increased progressively as the train approached Stockholm and corresponding increase occurred in the magnitude of the estimates expressing various forms of discomfort. The subjects with the longer trip (Nynäshamn) were found to have a lower rate of adrenaline excretion on the train than the subjects with. the shorter one (Västerhaninge). .The results indicate that the stress involved in travelling varies more with the social and ecological circumstances of the trip than with its length or duration.