A retrospective study was carried out to evaluate the role of varus proximal femoral osteotomy in relieving symptoms and improving function in adults affected by hip dysplasia. A group of 24 patients were identified that underwent 26 varus proximal femoral osteotomies between the period May 1979 and January 2001. All were investigated by dynamic hip arthrography to confirm restoration of congruency in the abducted position and the position of ''best fit''. The mean age of the patients at the time of operation was 26 years (range 16 to 47) and the median duration of follow-up was 5.1 years (range 1.6 to 23.1 years). Clinical improvement was evaluated by determining the Harris Hip Score at the time of admission with a further assessment at the most recent follow-up. Additionally, radiological change was evaluated by measuring acetabular femoral head index, the centre-edge angle of Wiberg and the Tonnis grade of osteoarthritis. The results revealed an improvement in Harris hip score from a mean of 72.1 pre-operatively (range 58.8 to 88.53) to 96.83 at the most recent follow-up (range 85.1 to 100). The centre edge angle and acetabular head index also increased in all patients. The results were statistically significant (p value <0.05). The procedure was found to reduce discomfort and improve function in patients affected by hip dysplasia. No patients required further intervention to alter disease progression during the follow-up period. The best results were found when the operation was performed for long leg dysplasia. Only one patient required surgery for non-union at the osteotomy site. Varus proximal femoral osteotomy appears to be a good treatment option in young adults with hip dysplasia, even when early degenerative change is present.