The role of heart catheterization continues to evolve as the sophistication of cardiac MRI and CT improves and the breadth of interventional catheter techniques widens. This analysis is approached from four perspectives: (1) planning of the procedure, including information required, potential pitfalls, and equipment; (2) performance of the procedure, including sample run, coronary arteriography, chamber angiography, and angiography of selected lesions; (3) current role of heart catheterization, considering the impact of echo, MRI, and CT on indications for catheterization procedures and current interventional procedures; and (4) new and emerging interventions and speculation as to the future role of diagnostic heart catheterization in patients who have adult congenital heart disease.