Overweight is a serious health risk and is prevalent in Australia. This study explored sex, socio-economic status and age differences in body mass index, the perceived effectiveness of weight-loss strategies and the frequency of their use, and awareness of the risks of obesity in a random sample of adult men (n = 457) and women (n = 537) from higher and lower socioeconomic areas. According to self-reports, 37 per cent of the sample were overweight or obese. More men than women, and more older than younger respondents, were overweight. There were no sex differences in the frequency of obesity. There were significantly more obese individuals in the lower than in the higher socioeconomic area. Women more frequently put themselves in a higher weight category while men more frequently put themselves in a lower weight category. Fifty-eight per cent of respondents reported the desire to lose weight and 24 per cent of the sample were trying to lose weight on the survey day; 46.9 per cent had attempted to lose weight in the previous 12 months, and these were more likely to be female, younger and obese or overweight. Only minor differences according to sex or socioeconomic status were found in beliefs about the effectiveness of different weight-loss strategies. However, older respondents were less likely to have exercised recently as a means of weight reduction. There was good recognition of diseases made worse by being overweight, although the health risk of male fat distribution patterns was not widely known.