Questionnaires were mailed to 2,160 persons selected from the Oakland, Calif., telephone directory; 1,212 (58%) were completed and returned and of these 224 Irish, 187 Jewish and 344 White Protestant questionnaires were selected for analysis. Of the 187 Jews, 52% had completed college and 52% had incomes of $10,000 or more, compared with 37 and 39% of the White Protestants and 28 and 35% of the Irish. The hypothesis to be tested was that the custom of frequent excessive drinking provides more fertile ground for the development of alcoholism than if drunkenness is rare. Daily drinking was reported by 36% of the Irish, 26% of the White Protestants and 18% of the Jews; drinking 3 or more drinks at a time 4 or more evenings a week was reported by 17%, 13% and 3%, respectively; and intoxication at least once in the last few months by 32%, 22% and 13%. Among those drinking 3 or more drinks at least 3 times a week, 52% of the Irish and 50% of the Jews report having been intoxicated, suggesting that among those who drink frequent substantial amounts a risk of problem drinking exists independently of cultural identity. Among the Irish, 50% were either abstainers (9%) or in the 2 highest drinking categories, whereas only 20% of the Jews were abstainers (4%) or in the highest drinking categories, suggesting a lack of uniformity in Irish drinking customs. Among the Irish, religion did not make a significant difference in drinking patterns: 26% of the Irish Catholics with Catholic wives and 26% of the Irish Protestants with Protestant wives reported recent intoxication. The Irish more consistently reported recent intoxication than either Protestants or Jews of the same education, income and age. Fewer first generation Irish (20%) and Jews (4%) reported intoxication than second (25 and 14%) or third generation (32 and 24%). But ethnic differences were not so apparent among the younger respondents with at least 1 parent born in the U. S. A.; all seem to be allowed to drink heavily; whereas in older respondents ethnicity was influential regardless of generation in U. S. A. Little differences in drinking patterns were found between Orthodox, Conservative and Reform Jews, although more Jews with no affiliation had been intoxicated (17%) than Reform (11%) or Conservative (12%). True—false answers to questions on attitudes toward drunkenness elicited surprisingly few differences: 45% of the Irish, 51% of the Protestants and 55% of the Jews regarded “drunks” as perfectly harmless, while 69, 75 and 61% thought the drunken man a disgusting sight. This apparent similarity might be a result of different definitions of drunkenness; in a further study of attitudes in a different sample (22 Jews, 75 Protestants and 69 Irish) using an open-ended questionnaire, fewer Jews (5%) than Protestants (9%) or Irish (8%) were sympathetic toward intoxicated persons, more Jews (65 vs. 44 and 36%) definitely disapproved, but fewer Jews (15 vs. 17 and 17%) expressed strong disapproval. Evidently Jews are less likely to approve and more likely to disapprove mildly of drunkenness than Irish and Protestants, but are also in general less likely to express intolerance.