New South Wales, Australia, is one of the major markets in the world for machine gaming, with its 1,441 registered clubs holding the dominant share of the state's machines. This study examined machine gambling behavior amongst a random sample of 3,000 club members from six of the largest clubs in Sydney, the capital city of New South Wales. The findings identify their machine gambling preferences and participation levels, isolate significant sociodemographic and other differences between gaming machine and non-gaming machine players, measure the prevalence of probable pathological gambling associated with machine gambling, and identify certain characteristics which differ significantly between probable pathological and non-pathological machine gamblers amongst the respondents.