Background: Psoriasis treatments are known to be costly, but little is known about the financial impact of psoriasis and the way in which it relates to the severity of the disease. Objective: This study was performed to obtain an estimate of the treatment costs faced by patients with psoriasis. Methods: A total of 578 anonymous mail surveys were distributed to patients with psoriasis; 318 surveys were returned (55%). Psoriasis severity was assessed with the previously validated Self-Administered Psoriasis Area Severity Index (SAPASI). Results: The total and out-of-pocket expenses to care for psoriasis were correlated with psoriasis severity (r = 0.26, p = 0.0001). There were no sex (p = 0.9) or racial (p = 0.4) differences in total expenditures. Severity was correlated with how bothersome to the patient was the cost of treatment (r = 0.30, p = 0.0001), the time required for treatment (r = 0.38, p = 0.0001), and the time lost from work (r = 0.23, p = 0.0001). Lower quality of life at work and in money matters also correlated with severity of psoriasis. Higher family income was associated with less time spent caring for psoriasis and less interference with work around the home. Conclusion: As expected, the expenses caring for psoriasis are greater for patients with more severe disease. These costs and other financial implications are associated with lower quality of life for patients with more severe psoriasis. (J Am Acad Dermatol 1997;37:564-9.)