To identify the correlates of a second restenosis after repeat percutaneous coronary angioplasty, the records of 384 patients with single vessel disease who underwent repeat angioplasty for restenosis complicating a first elective angioplasty were examined. A second restenosis occurred in 47 (31%) of 151 patients having angiographic follow-up. Univariate correlates of a second restenosis were an interval between the first and second angioplasty less than 5 months (41 versus 20% of patients had restenosis, p less than 0.01), male gender (35 versus 12%, p less than 0.05), lesions length greater than or equal to 15 mm before the second angioplasty (62 versus 28%, p less than 0.05), diameter stenosis greater than 90% before the second angioplasty (67 versus 29%, p less than 0.05), final gradient greater than 20 mm Hg after the second angioplasty (52 versus 28%, p less than 0.05) and an additional site requiring dilation at the time of the second angioplasty (50 versus 29%, p = 0.10). Multivariate predictors of a second restenosis were an interval of less than 5 months between the first and the second angioplasty (p = 0.001), male gender (p = 0.001), lesion length greater than or equal to 15 mm before the second angioplasty (p = 0.001) and the need to have an additional site dilated at the time of the second angioplasty (p = 0.002). Patients at increased risk of restenosis after the second angioplasty can be identified and may serve as a useful population for intervention studies.