Left ventricular, and possibly also right ventricular, mass is an important determinant of prognosis in cardiovascular disease. Consequently, noninvasive estimation of ventricular mass may be an important clinical investigation. The ideal technique for this purpose would be widely available and accurate, employ short study times and avoid exposure to contrast agents and radiation. Conventional nuclear magnetic resonance (NMR) imaging fulfills most of these criteria, but it is time-consuming and expensive. Moreover, its accuracy in estimating right ventricular mass has yet to be assessed. Accordingly, high speed NMR imaging using the snapshot gradient echo technique was used to assess right and left ventricular mass in 10 dogs and the results were compared with values obtained at autopsy, which ranged from 26.1 to 52.9 and 61 to 119.8 g. respectively. The mean absolute difference between the NMR imaging estimates and autopsy findings was 2 ± 1.2 g (range 0.4 to 4.2) for right ventricular mass and 4.4 ± 1.7 g (range 1.8 to 6.6) for left ventricular mass. Total NMR imaging time was ≤5 min. These data demonstrate that high speed NMR imaging can be used to accurately estimate right as well as left ventricular mass.