Of the last 200 consecutive patients undergoing PTCA procedures at our institution, 29 (15%) had unstable angina; and angioplasty was performed at the time of diagnostic coronary arteriography. There were 26 males and three females with an age range of 31-82 (mean 57) years. Factors favoring PTCA at the time of initial coronary arteriography included clinical indications for revascularization, appropriate anatomy based on high-quality fluoroscopy, and availability of emergency surgery if required. Of 34 coronary lesions in 29 patients, 19 involved the anterior branch of the left anterior descending coronary artery (LAD), eight the circumflex branch (Cx); and seven the right coronary artery (RCA). Five patients had two vessels dilated (one LAD + RCA, two LAD + Cx, and two RCA + Cx). Of the coronary artery lesions, 19 were concentric, seven were eccentric, 20 were single and discrete, six were long or multiple in the same vessel; eight vessels were totally occluded, and in nine patients there was good collateral circulation. Twenty-nine (85%) arteries were successfully dilated. Of the unsuccessful cases, one was from failure to cross a totally occluded lesion, and three residual lesions and/or postdilatation pressure gradients remained significant. One patient required emergency aortocoronary bypass surgery because of total occlusion of the LAD immediately post-PTCA. There were no postprocedural myocardial infarcts or deaths. It is concluded that, in selected patients with unstable angina, PTCA can be performed successfully and with low risk at the time of initial diagnostic coronary arteriography. This approach offers certain clinical financial advantages.