We examined whether physical activity risk differed between migrant sub-groups and the Australian-born population.Data were drawn from the Australian National Health Survey (2001) and each resident's country of birth was classified into one of 13 regions. Data were gathered on each resident's physical activity level in the fortnight preceding the survey. Multivariable logistic regression, adjusted for potential confounders examined the risk of physical inactivity of participants from each of the 13 regions compared to the Australian-born population.There was a greater prevalence of physical inactivity for female immigrants from most regions compared to male immigrants from a like region. Immigrants from South East Asia (OR 2.04% 95% CI 1.63, 2.56), Other Asia (OR 1.53 95% CI 1.10, 2.13), Other Oceania (1.81 95% CI 1.11, 2.95), the Middle East (OR 1.42 95% CI 0.97, 2.06 [note: border line significance]) and Southern & Eastern Europe are at a significantly higher risk of being physically inactive compared to those born in Australian. In contrast, immigrants from New Zealand (OR 0.77 95% CI 0.62, 0.94), the UK & Ireland (OR 0.82 95% CI 0.73, 0.92), and other Africa (OR 0.69 95% CI 0.51, 0.94) are at a significantly lower risk of being physically inactive compared to the Australian born population.Future research identifying potential barriers and facilitators to participation in physical activity will inform culturally sensitive physical activity programs that aim to encourage members of specific regional ethnic sub-groups to undertake physical activity.