Finite element models of diseased arteries subject to balloon dilation are used to study the stresses in the arterial wall and plaque at peak balloon pressures. These models incorporate large strain, simulate contact between the balloon and the inner artery, and the constituent materials are modeled as nonlinear elastic. In these analyses, balloon dilation pressures range from 300 to 450 kPa. The stress in the diseased artery is recorded under different stenosis levels dilated using different balloons and possible causes of restenosis and plaque rupture are discussed.