Applications of CFD to simulation of non-cavitating and cavitating flow around a marine propeller are presented in this paper. The influence of the turbulence model and the grid resolution on the accuracy of the propeller performance prediction has been systematically investigated, and the condition for obtainining grid-independent thrust and torque coefficients is proposed. Validations carried out for two conventional propellers have shown that quantitative agreement with experiment is achieved at non-cavitating condition. By applying a cavitation model, cavitating flows around a propeller both in uniform and non-uniform flows are also simulated. Comparisons with experiments have shown that the cavity shape and the variation of the cavity volume are qualitatively reproduced. However, it has been also indicated that the present cavitation model is insufficient in accuracy and stability.