Objectives. To determine whether the outcome of secondary open pyeloplasty is compromised by previous retrograde balloon dilation. Methods. Patients undergoing secondary open pyeloplasty after retrograde balloon dilation (n = 25) were compared with a similar group undergoing primary open pyeloplasty (n = 25) at the same institution. Patients were assessed by renography before and after surgery, and postoperative success was determined by the complete absence of pain. Results. In the primary pyeloplasty group, the success rate was 96%, with a mean follow-up of 33 months (range 17 to 53). In the secondary pyeloplasty group, the success rate was 88%, with a mean follow-up of 20 months (range 9 to 32). No statistically significant difference was found in the success rates between the two groups (P = 0.6). Conclusions. Treatment failures after retrograde balloon dilation can be salvaged by secondary pyeloplasty with no detriment to the chance of long-term success compared with primary pyeloplasty.