The prevalence of psoriasis in a defined semi-urban general practice population of 5395 was estimated by means of a postal questionnaire, describing the features of psoriasis followed by physical examination of positive responders, and by a practice disease register, which directly identified psoriatic patients. A point prevalence of 1.48% was found based on examination at the time of study with an equal sex distribution. The mean age of development of the disease was 33 years. At the time of examination, the disease was mild in most patients (mean PASI 2.87). However, there was evidence of marked variability in severity within individuals with time. At some stage, 60% of individuals had required referral to a consultant dermatologist, and approximately 50% of these had received second-line, i.e. non-topical, treatments. Approximately 25% of patients had been in remission at some stage. Forty-one per cent of patients were aware that psoriasis was a genetically determined disease and 37% thought that stress was an exacerbating factor. Seventy per cent of patients were aware that the condition was not curable, but 63% thought that treatment was worthwhile. Fifty-three per cent described themselves as 'bothered' by the appearance of the condition. This concern was positively (and inversely) related to current age, and to stress as an exacerbating factor, but not to sex, PASI, duration of psoriasis, previous hospital referral, or the presence of pruritus. In this study of psoriasis in the community, the findings, particularly in relation to patients' attitude to the disease, disease severity, fluctuation in severity and referral requirements, are of potential interest in health care planning.