The Salter innominate osteotomy has been used successfully for many years in the treatment of developmental dysplasia of the hip. One of its main drawbacks is the need for internal fixation with pins and their subsequent removal. We describe a modification of this osteotomy that does not require pin fixation and secondary removal. We retrospectively reviewed 114 hips in 94 patients who had been operated on by a single surgeon. An oblique rather than the original horizontal osteotomy was used without internal fixation. There were 80 female and 14 male patients. The mean age at operation was 25 months (18 to 84) and the mean follow-up was 30 months (12 to 88). Most patients required additional open reduction and capsuloplasty. The mean pre-operative acetabular index was 37.9 (24 to 54), which decreased to 19.9 (7 to 29) in the immediate post-operative period, and improved to 14.6 (5 to 25) at the final follow-up (student's t-test, p < 0.0001).