BACKGROUND: Childhood idiopathic chondrolysis of the hip (ICH) causes progressive destruction of the articular cartilage of the hip joint with associated bone remodelling. The MRI features of this disease have not previously been described. OBJECTIVE: To document the MRI features of childhood ICH and determine which features may help distinguish ICH from other causes of hip joint destruction in the paediatric population. MATERIALS AND METHODS: A retrospective review of the MRI examinations of children with clinically diagnosed ICH. All children had undergone synovial biopsy and/or joint aspiration with plain hip radiography to exclude causes of secondary chondrolysis. RESULTS: Ten MRI examinations were performed on six children. Cartilage loss, small hip joint effusions, bone remodelling and significant regional muscle wasting were seen in all children. Cartilage loss was most severe in the central part of the joint. Synovial enhancement was not a constant feature of ICH. Serial imaging in three children showed disease progression. CONCLUSIONS: MRI in ICH clearly demonstrates cartilage loss and enables delineation of bone and muscle abnormalities. It is helpful in the differential diagnosis of hip joint disease in children and may provide further information on the progression and aetiology of ICH.