Over the past decade, utilization of cardiac catheterization for preoperative hemodynamic assessment of patients with mitral and aortic stenosis has steadily decreased. The reason for this trend is the use of echocardiography, which is emerging as a gold standard for clinical characterization of valvular lesions. Since cardiac catheterization is an invasive procedure that is associated with a significant percentage of complications, echocardiographic evaluation of patients with valvular stenosis is safer and more cost-effective. In the next millennium, echocardiography will probably completely replace the use of catheterization for hemodynamic assessment of the severity of mitral and aortic stenosis.