Phototherapy is highly effective in the therapy of psoriasis, but patient access to phototherapeutic facilities is not universal. Commercial tanning facilities are universal, but their efficacy in psoriasis treatment is unestablished. Our purpose was to conduct a study to assess the effect of a commercial tanning unit outfitted with nonprescription lamps on psoriasis. We conducted a 6-wk open study of 20 adult patients with stable psoriasis vulgaris. Clinical response was defined as a decrease in the Psoriasis Area Severity Index (PASI) or the Self-Administered PASI (SAPASI) by > or = 10%. There were 16 men and 4 women who participated with a mean (+/-SD) age of 43.0 +/- 14.8 y. Initial and final health-related quality of life information collected included the following instruments: the Brief Symptom Inventory (BSI), the Psoriasis-Related Stressor Scale (PRSS), and the Psoriasis Disability Scale (PDS). Side effects of tanning therapy were closely monitored. Fifteen subjects completed the entire 6-wk trial, and exit data on all subjects were used for analysis. The mean number of tanning sessions was 19 +/- 7.6 with a median of 19 and range of 3 to 29. Analysis of all 20 enrolled subjects found that 16 (80%) showed clinical response as measured by PASI, whereas 17 (85%) showed SAPASI response. Initial and final PASI scores decreased (p = 0.0001) from 7.96 +/- 1.77 to 5.04 +/- 2.5, and SAPASI scores also decreased (p = 0.02) from 11.8 +/- 4.4 to 7.9 +/- 7.7. When controlled for age and sex, a dose-response relationship was demonstrated with the PASI and SAPASI (p < 0.02). Decreases in the mean BSI and PRSS scales were demonstrated (p < 0.02), confirming the clinical significance of the reductions in disease severity scores. Episodes of mild burning occurred in 7 of 20 (35%) participants. Three subjects reported itching after one or two tanning sessions. This study showed that a tested commercial nonprescription tanning unit improved both psoriasis severity and health-related quality of life. Commercial tanning bed treatments may be a useful approach in patients unable to obtain office-based ultraviolet treatments.