OBJECTIVES: Empirical evidence for the efficacy of drugs and therapeutic procedures has become crucial for reimbursement and for use in praxis. Beyond that, assessment of patient benefit from the patient’s perspective is of particular relevance. The PBI for skin diseases is a validated instrument developed to measure patient-relevant benefits in dermatology. So far, no specific validation data on such an instrument for psoriasis have been published. Objective of this study was the validation of PBI specifically for psoriasis treatment. METHODS: Patient-relevant treatment needs were recorded with the “Patient Needs Questionnaire” (PNQ) and patient benefits from treatment were assessed using the “Patient Benefit Questionnaire” (PBQ), both containing identical items with different wording. Data were obtained from two studies, one being a cross-sectional study on n=2,009 patients, the other a prospective observational therapeutic study on n=93 patients.  Treatment goals and benefits were used to calculate the overall preference-based Patient Benefit Index (PBI). RESULTS: In both studies, the PNQ showed a variety of high therapeutic needs from the perspective of the psoriasis patients. The PBQ questionnaire revealed that under routine treatment only a part of the patient-defined goal were achieved. The resulting PBI depended on the treatment applied. Higher values were observed in systemic treatments, in particular in biologics. The PBI was feasible with a rate of missing values ≤1.5% in PNQ and ≤2.0% in PBQ. The subscales of the PBI were internally consistent (Cronbach’s alpha = 0.68 – 0.87). The PBI showed satisfying convergent validity with respect to correlation with changes in QoL (delta DLQI) and PASI. Moreover, correlation with separate single items on treatment benefit (anchoring variables) was markedly high (r=0.75, r=0.65, p<0.001). CONCLUSIONS: The Patient Benefit Index (PBI) is a valid, reliable and suitable instrument for the assessment of patient-reported benefit in the treatment of psoriasis.