The objective of this investigation was to develop a computational methodology to quantify propeller performance in icing conditions and to identify areas where additional research is required. Propeller blade-section ice geometry was predicted using the ice accretion code LEWICE, the corresponding degradation in blade-section aerodynamic performance was predicted using the RANS code Fluent, and the blade-section performance was correlated to propeller performance with a blade-element code utilizing vortex theory. The results of this process were compared to experimental data obtained during a full-scale propeller icing test conducted at McKinley Climatic Laboratory at Eglin AFB. Ice shedding was found to be significant during these tests, and LEWICE was only able to accurately predict blade-section ice geometries by accounting for this shedding using experimental observations. Fluent predictions of blade-section aerodynamic performance were compared with experimental measurements obtained with artificial ice shapes in an earlier part of this investigation; agreement ranged from poor to good, depending on the blade section and ice geometry. The resulting predictions in clean and iced propeller performance were within 10% of the experimentally-measured values for two of the three icing conditions presented, and within 17% for the third set of conditions. This study has identified areas where research is needed to improve the accuracy of the predictions.