We have developed a new small animal model of obesity in which rabbits fed a high diet develop abnormalities in common with obese humans, including left ventricular (LV) hypertrophy. Using M-mode and two dimensional Doppler echocardiography we examined the characteristics of LV hypertrophy and diastolic function in obese and lean rabbits. Obese rabbits had greater interventricular septum and LV posterior wall thickness and greater LV internal end-diastolic and end-systolic diameters. Functionally, obese rabbits had higher A/E ratios. Similarly to obese humans, obese hypertensive rabbits developed combined concentric and eccentric LV hypertrophy and diastolic filling abnormalities. Therefore, this model may be valuable in the study of the development and pathology of obesity-related LV hypertrophy.