A sample survey of 1000 households in Sydney was undertaken in 1968–69; questionnaires were completed by 820 respondents aged 15 and over. According to their quantity and frequency of drinking, the respondents were divided into 6 categories: heavy drinkers (48% of the 373 men, 15% of the 447 women); moderate-frequent drinkers (19 and 12%); moderate-infrequent (7 and 13%); light-frequent (6 and 14%); light-infrequent (11 and 29%); and abstainers (9 and 18%). In the age group 20–24, 68% of the men and 38% of the women were heavy and moderate-frequent drinkers; at age 50–59, 74 and 35%; and over age 60, 58 and 8%. Light-infrequent drinking was the mode in boys aged 15–17; heavy drinking in boys aged 18–19. Among girls aged 15–19 light-infrequent drinking was the mode. Of those with only primary school education, 58% of the men and 20% of the women were heavy and moderate-frequent drinkers, compared with 75 and 32% of the university educated. Among men no important occupational differences in heavy drinking were found, but the proportion of moderate-frequent drinkers decreased from 25% of the upper professional and managerial group to 10% of the miners, farm workers and laborers, while the proportion of abstainers and light-infrequent drinkers increased from 15 to 25%. Among women more of the highest occupational groups were heavy drinkers. Among the highest income group, 76% of the men and 36% of the women were heavy and moderate-frequent drinkers, compared with 40 and 16% of the lowest income group; 12 and 31% of the highest income group were abstainers and light-infrequent drinkers, compared with 47 and 68% of the lowest income group. No direct relationship between social class and drinking pattern was found. Forty per cent of the single men and 50% of the married were heavy drinkers; 5% of the single women and 16% of the married were light-frequent drinkers and 18 and 12% were moderate-infrequent drinkers. Abstinence was the mode among widows. Among men no differences in drinking patterns by migrant status (place of birth of respondent and parents) were found, but among the women 17% of those born abroad were moderate-frequent drinkers and 10% of those born in Australia. Drinking patterns in the 3 largest religious denominations were similar: 69% of the Anglican men, 67% of the Catholic men and 72% of the Presbyterian men were heavy and moderate-frequent drinkers, while 21, 17 and 9%, respectively, were light-infrequent drinkers and abstainers; the respective proportions among women were 27, 30 and 25% and 48, 39 and 40%. Since heavy drinking is the normative behavior of Sydney men, such drinking will be socially accepted and even encouraged, thus providing a social context highly conducive to the development of alcoholism in susceptible persons.