Little is known about the effects of the composition of dietary carbohydrate on the development of left ventricular hypertrophy (LVH) and heart failure (HF) under conditions of pressure overload. The objective of this study was to determine the effect of carbohydrate composition on LVH, LV function and mortality in a mouse model of chronic pressure overload. Male C57BL/6J mice 6 weeks of age (n = 14-16/group) underwent transverse aortic constriction (TAC) or sham surgery and were fed either standard chow (STD; 32% corn starch, 35% sucrose, 3% maltodextrin, 10 % fat expressed as a percent of the total energy), high starch chow (Starch; 58% corn starch, 12% maltodextrin, 10% fat), or high fructose chow (Fructose; 9% corn starch, 61% fructose, 10% fat). After 16 weeks of treatment, mice with TAC fed the STD or high fructose diets exhibited increased LV mass, larger end diastolic and systolic diameters, and decreased ejection fraction compared to sham. The high starch diet, in contrast, prevented changes in LV dimensions and contractile function. Cardiac mRNA for myosin heavy chain was increased dramatically in the fructose-fed banded animals, as was mortality (54% compared to 8% and 29% in the Starch and STD banded groups, respectively). In conclusion, a diet high in simple sugar was deleterious, resulting in the highest mortality and expression of molecular markers of cardiac dysfunction in TAC animals compared to sham, while a high starch diet blunted mortality, increases in cardiac mass, and contractile dysfunction.