Background and Design: Psoriasis causes impairments in many daily activities, such as sleeping and occupational performance. One of the most important factors determining the quality of life of a person is sleeping. Studies about sleep quality in psoriasis are quite limited. In this study, we aimed to assess the quality of sleep and to examine the factors affecting the quality of sleep in patients with psoriasis. Materials and Methods: Seventy-three patients with psoriasis and 73 healthy subjects were included in the study. A sociodemographic data form was completed by all the participants and the Pittsburgh Sleep Quality Index (PSQI), 36-item Short-form Health Survey (SF-36), Hamilton Depression Rating Scale (HAM-D) and the Hamilton Anxiety Rating Scale (HAM-A) were administered to the patients and controls. Body Mass Index (BMI) was calculated in patient and control groups. The Psoriasis Area Severity Index (PASI) and Dermatology Life Quality Index (DLQI) were administered and pruritus was assessed in patient group. Results: PSQI global scores in patient group were found to be higher than in control group. Quality of sleep was worse in patient group. Severity of disease and sociodemographic features were found to be factors not affecting the quality of sleep. In patient group, the patients with higher sleep disturbances had higher rates of depression and anxiety scores. In patient group, the patients with severe pruritus had worse sleep quality. Conclusion: Psoriasis and psoriatic symptoms including pruritus impair sleep quality. Assessment of sleep quality and new strategies to improve sleep quality in patients with psoriasis may help improve quality of life. (Turkderm 2015; 49: 208-12)