The assessment of physical activity by questionnaire is currently the most popular and practical method of quantifying physical activity levels. Many questionnaires, past and present, have considered overall or habitual physical activity, which includes occupational (or nonleisure) activity. Others have focused specifically on leisure-time physical activity (LTPA) owing to the recognition of its dominating contribution to the total physical activity of developed populations. This review covers questionnaires that wholly or in part attend to LTPA levels. Typically, self-complete or interviewer-administered questionnaires record information on the types, frequency and duration of activities performed over a particular period of time. Activity-specific energy cost values, expressed in metabolic equivalents (METS) or kilocalories, are then commonly used to estimate the total energy expenditure from all activities and/or categories of activities. The validation of LTPA questionnaires has had to rely upon indirect methods, such as the assessment of cardiorespiratory fitness, body composition and activity diaries. The reporting of the reliability of questionnaires has frequently been ignored, although in cases where it has been reported, doubt exists as to whether the consistency of the questionnaire or the consistency of subjects' physical activity habits were being examined. LTPA questionnaires first appeared in the literature in the mid-1960s for use among specific, mainly middle-aged male population groups. Though they varied in their modes of scoring, periods of activity recall, and overall complexity, associations were universally observed between physical activity levels and chronic health conditions. However, it became apparent that different questionnaires did not yield the same results. In 1978, a questionnaire to assess only LTPA, the Minnesota LTPA Questionnaire, was published and despite its substantial limitations, has since established itself as the most popular option available. In recent years, shorter and simpler alternatives have been advocated, though most have yet to be adequately scrutinised. Associations have been found between LTPA and fitness levels, prompting the use of LTPA questionnaires in large-scale fitness surveys of both adults and children. Although LTPA has continued to be estimated in terms of energy expenditure, little attempt has been made to extend existing knowledge on the energy cost of physical activities. Existing values do not accommodate for individual intensities and inter-population activity variations. Consequently, standardised questionnaires are not yet viable. There exists considerable scope for further work with LTPA questionnaires, especially since the association between coronary heart disease and physical activity is now well recognised. Efforts ought to be directed at wider social groups for whom leisure-time activity may have distinct implications.