A parametric study was conducted, using the finite-element method, to study the load distribution characteristics of curved composite I-girder bridges under truck loading. The influence of several geometric parameters on the moment, and deflection distribution factors, as well as warping stresses in straight and curved composite I-girder bridges was examined. For straight bridges, the moment distribution factors were correlated with those specified in the Canadian Highway Bridge Design Code of 2000, CHBDC. Also the magnitudes of warping stresses in the steel bottom flanges were correlated with the specified limits in bridge codes. The results showed that the CHBDC moment distribution factors significantly overestimate the structural response of straight bridges considered in this study. It was also observed that the curvature limitation specified in the CHBDC to treat a curved bridge of low curvature as a straight one underestimate the structural response.