In 1977, a female patient, aged 31y, presented with histiocytosis X in the right pelvis and was treated with radiotherapy. She presented again in 1999 at the age of 53y with a similar problem at the same location this time also involving the acetabulum. The affected right hip was treated with cemented total hip replacement. Two years postoperatively, the patient was pain free with no evidence of local recurrence or loosening of implant, thus demonstrating that total hip replacement is a viable treatment option for histiocytosis involving the hip.