Femur-acetabular impingement is a recently discovered etiology of early hip osteoarthritis. Patient history and clinical examination allow to make the diagnosis, whereas the radiological exams allow to find the etiology of impingement. Impingement is related to morphological alterations of the acetabular rim and/or proximal femur, leading to an abnormal contact between the articular components. The localisation of the abnormal morphology determines the type of impingement and the resulting articular damages. Because of the increasing risk of chondral lesions, only an early treatment may eventually improve the prognosis of the hip joint. If primary conservative treatment is unsuccessful in confirmed impingement cases, open or arthroscopic surgical treatment is indicated.