Osseous lesions have been reported in only 1-2% of patients with hydatid disease. Joint involvement is usually due to secondary extension from the adjacent bone, although primary hydatid synovitis after haematogenous spread of the infection can be seen. We present a long-term radiological follow-up (12 yr) in a patient who developed hydatid disease of the left pelvic and femoral bones with cartilage destruction of the ipsilateral hip joint. After a Girdlestone arthroplasty, she received mebendazole (3 g/day) for 10 yr and albendazole (400 mg/day) for 2 yr with radiological impairment of the lesions. Complete surgical excision is the treatment of choice for osseous hydatid disease. Isolated medical therapy with mebendazole or albendazole is not adequate for controlling the process, but it can be added to surgery or, as in our case, used like isolated therapy when complete excision is not possible.