Restenosis after percutaneous transluminal coronary angioplasty (PTCA) cannot currently be prevented. Different medical regimens have been largely unsuccessful. Experimental studies suggest roles for beta-adrenergic blockers and calcium antagonists. Controlled clinical studies have failed to show any decrease in restenosis rate for calcium antagonists. Corresponding studies for beta blockers are lacking. This study evaluates 541 consecutive PTCA procedures, 455 (86%) in patients treated with beta blockers after PTCA (76% metoprolol, 14% atenolol, 4% sotalol, 6% others) and 86 (14%) in patients without beta blockers. Angiographic success was achieved in 483 of 620 lesions (78%), and was not significantly different with or without beta blockers (79 vs 73%, p greater than 0.05). The procedure success rate and the complication rates (myocardial infarction, emergency coronary artery bypass grafting, death) did not differ with or without beta blockers (p greater than 0.05). Follow-up angiograms for 426 of the 483 successfully dilated lesions (88%) revealed that a total of 155 stenoses had recurred (36%). The restenosis rate was not significantly different with (368) or without (58) beta blockers (36 vs 38%, p greater than 0.05). For beta blockers with calcium antagonists (84% nifedipine, 13% diltiazem, 2% verapamil, 1% others), the restenosis rate was 97 of 250 (39%) vs 36 of 118 (31%) (p greater than 0.05). This retrospective study indicates that treatment with beta-adrenergic blockers after PTCA, alone or in combination with calcium antagonists, does not influence either the success rate or the restenosis rate and can be continued if indicated from an antiischemic viewpoint.