The modified Ross procedure, which involves replacement of the aortic valve with a pulmonary autograft root supported within a Dacron tube graft, was developed with the goal of preventing late autograft dilatation and associated aortic insufficiency. The case is reported of an adult patient who had a bicuspid aortic valve (BAV), underwent a modified Ross procedure, and developed severe aortic insufficiency within one year and subsequently required reoperation for aortic valve replacement. While advances have been made to increase the success of the Ross procedure via modifications to prevent aortic root dilatation, no modifications have yet been devised to improve the ability of the pulmonary valve to withstand systemic aortic pressures. The Ross procedure has significant advantages for children, but the risks and benefits should be carefully considered in adults, especially in those with BAV.