A two-stage psychiatric survey of a random samples of adults aged 18-64 from Camberwell is described. Agency interviewers carried out the first stage (N = 800), using the shorter form of the Present State Examination (PSE). MRC interviewers, using the full PSE, saw a stratified sample of these (N = 310) in the second stage. A second interview was sought with all those of Index of Definition (ID) level 5 and above at the first interview ("cases") and with random sample of those below that level 20.9% refused or were never available for the first interview. Of the 800 subjects successfully interviewed, 10% refused a further interview and 124% of those finally selected for this interview were either unavailable or changed their minds. The MRC data, weighted to represent the whole sample, are used in our analyses. The prevalence of psychiatric disorder as defined in our study was calculated at 6.1% for men and 14.9% for women. Women showed a higher prevalence of disorder in the age-groups 25-34 and 45-54, but in men there was no significant association with age. In contrast to the findings of Brown & Harris (1978), social class did not have a strong association with disorder. Single men had much higher rates than married men, while the reverse was true in women. In both sexes employment was associated with lower rates of disorder. An attempt to explain the high prevalence in women in terms of their role in marriage and child-care was only partly successful.