Using a prospectively collected database of patients undergoing cardiac catheterization, we sought to compare the outcomes of procedures performed by supervised physician assistants (PAs) with those performed by supervised cardiology fellows-in-training. Outcome measures included procedural length, fluoroscopy use, volume of contrast media, and complications including myocardial infarction, stroke, arrhythmia requiring defibrillation or pacemaker placement, pulmonary edema requiring intubation, and vascular complications. Class 3 and 4 congestive heart failure was more common in patients who underwent procedures by fellows compared with those undergoing procedures by PAs (P = 0.001). PA cases tended to be slightly faster (P = 0.05) with less fluoroscopic time (P < 0.001). The incidence of major complications within 24 hr of the procedure was similar between the two groups (0.54% in PA cases and 0.58% in fellow cases). Under the supervision of experienced attending cardiologists, trained PAs can perform diagnostic cardiac catheterization, including coronary angiography, with complication rates similar to those of cardiology fellows-in-training.