Physical inactivity is a modifiable risk factor of many non-communicable diseases. The aim of this study was to assess the pattern of physical activity among Sri Lankan adults in the district of Colombo, Sri Lanka. The study was carried out among a sample of 1320 adults aged 20 to 59 years, selected using stratified, cluster sampling method. Physical activity was assessed using the long form of the International Physical Activity Questionnaire validated for Sri Lanka. The prevalence of sufficient physical activity was 82.0% (CI = 78.5-85.0) for males and 79.7% (CI = 76.5-82.6) for females. The odds of having sufficient activity were lower with increase in the level of urbanisation. Activity was achieved mainly through domestic and transport related activity. Only 21.7% carried out at least some activity for leisure. As Sri Lanka continues to urbanize, it is important to find strategies to increase the level of activity especially at leisure.