BACKGROUND: Available psoriasis surveys offer valuable information about psoriasis and psoriatic arthritis (PsA), but are limited by methodology or enrollment requirements. OBJECTIVE: To further the understanding of the unmet needs of psoriasis and PsA patients. METHODS: This was a large, multinational, population-based survey of psoriasis and/or PsA patients in North America and Europe. Patients were selected by list-assisted random digit dialing and did not have to currently be under the care of a health care provider, a patient organization member, or receiving treatment; 139,948 households were screened and 3426 patients completed the survey. RESULTS: The prevalence of psoriasis/PsA ranged from 1.4% to 3.3%; 79% had psoriasis alone and 21% had PsA. When rating disease severity at its worst, 27% (psoriasis) and 53% (PsA +/- psoriasis) of patients rated it as severe. Psoriasis patients indicated that their most bothersome signs or symptoms were itching (43%), scales (23%), and flaking (20%). Of psoriasis patients, 45% had not seen a physician in a year; >80% of psoriasis patients with >/= 4 palms body surface area and 59% of PsA patients were receiving no treatment or topical treatment only. Of patients who had received oral or biologic therapy, 57% and 45%, respectively, discontinued therapy, most often for safety/tolerability reasons and a lack/loss of efficacy. LIMITATIONS: The survey lacked a control group, did not account for ethnic and health care system differences across countries, and was limited by factors associated with any patient survey, including accurate recall and interpretation of questions. CONCLUSIONS: Several identified unmet needs warrant additional attention and action, including improved severity assessment, PsA screening, patient awareness, and treatment options.