Purpose To compare ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) determination of diffuse liver steatosis. Materials and methods Quantification of liver steatosis on ultrasound, CT, and MRI was correlated with histopathology in 67 patients. Results Opposed-phase MRI demonstrated the highest correlation with steatosis (0.68 and 0.69, P<.01; intraclass correlation coefficient, 0.93). Spearman’s correlation (and intraclass correlation) coefficients were lowest for ultrasound [0.54, 0.33 (0.40)] and enhanced CT [0.33, 0.39 (0.97)]. Conclusion Opposed-phase MRI demonstrated best overall performance for determining steatosis.