In this paper the important mechanisms affecting the deterioration of Arctic icebergs are modeled based on parameterizations developed for the International Ice Patrol. The model simulations of the deterioration of three icebergs in the Grand Banks/Labrador Sea area off the Canadian east coast are compared with observations. The model parameterizations provide a reasonable approximation of iceberg deterioration with best results being obtained where detailed observations of the above-water and underwater portions of the iceberg are available enabling accurate estimations of iceberg mass and other parameters needed for the model. A quantitative assessment of the deterioration of icebergs in the Grand Banks/Labrador Sea area is also carried out for each month of the year when the sea surface temperature was above zero. Wave erosion is found to be the major deterioration mechanism. Wave erosion and the resulting calving of overhanging slabs together account for more than 80 percent of the deterioration rate. A small iceberg drifting on the Grand Banks could lose up to one third of its mass in one day.