The Order Accumulation and Sortation Systems (OASS) are getting more important as distribution centers try to gain competitive advantages. The parameters that affect the sorting time in OASS are analyzed in this study. The length and speed of conveyors, sending the packages within a wave, the wave size, number of the sorting lanes and the sorting strategy are the main parameter in OASS. The time required to sort mixed items depends on the sortation strategy used as well. Different sorting strategies and different conveyor models are analyzed in this study. Available analytical models assume that all orders are at the same size (quantity). In this study this assumption also is relaxed. Simulation models have been developed to compare different design alternatives and design strategies. For different order combinations and for various design choices, simulation is used to compare sortation strategies. The results have been given in tables that show which strategy should be used under which scenario. Auto Mod Software is used as the simulation tool.