The travelling mail office clerks are shown, by medical examination and sociopsychological questionnaire, to be a very homogeneous naturally self-selected group with a low average age. The analysis of tasks shows a disadvantageous distribution of some main tasks over the work shift. Energy expenditure and cardio-vascular strain above physiological endurance limits occur mainly with the tasks of loading, handling and emptying mail bags. Environmental factors are mainly within acceptable standards. Fast-time simulation studies show that proposals can be made for organisation work (by job rotation) and selection of TMO clerks based on their individual working capacity.