Psoriasis has a substantial impact on patients' quality of life. The aims of this study were to assess the impact of the clinical severity of psoriasis on patients' quality of life and to determine the effects of psoriasis-related stress on patients' everyday life. The cross-sectional study was conducted at the Institute of Dermatovenereology, Clinical Center of Serbia, Belgrade. The study included 201 patients (124 men and 77 women), aged 18-70 with a diagnosis of psoriasis, hospitalized or treated as outpatients during 2009. For the assessment of patients' quality of life, the psoriasis disability index (PDI) was used. The stress related to psoriasis was measured with the psoriasis life stress inventory (PLSI) and disease severity with the psoriasis area and severity index (PASI). We found moderate correlation between PLSI and all PDI subscales and overall score (correlation coefficients ranged from 0.334 to 0.521). The correlation between PASI and PDI subscales was weak, while we failed to find any significant correlation between PASI and the PLSI. The results of multiple regression analysis indicated that stress, more severe disease, and lower educational level are significant determining factors of a poorer quality of life in patients with psoriasis. Our results support the importance of assessing the quality of life in psoriasis and effects of stress in patients' adjustment to their condition and may have important implications for a psychological stress management approach in the clinical management of psoriasis.