Background: The aim of our study was to determine the prevalence of ankle involvement in psoriatic arthritis (PsA) and to investigate its clinical and radiological aspects. Methods: Cross-sectional, monocentric study. All participants with RPso underwent a complete clinical examination, standard radiographs of both ankles, and osteoarticular ultrasonography. Results: We included 40 patients (mean age: 49.9 years, sex ratio M/F: 1.2). The clinico-radiological form was pure peripheral (52.5%), axial and peripheral (42.5%) or pure axial (5%). Talocrural involvement was present in 50%, and revealed the disease in 25% of cases. Standard radiographs were normal in 70% of cases, and abnormal in 30%. Ultrasonographic abnormalities of the ankle were observed in 42.5% of cases, and this involvement was infra-radiological in 47% of cases. A significant correlation was demonstrated between talocrural involvement and HAQ functional score (p=0.04). Conclusion: Ankle involvement is frequent and constitutes a major source of functional disability in RPso.