This article describes the modification, use, and validation of a three-dimensional computational fluid dynamics (CFD) code applied to model solid-cone sprays produced by pressure-swirl atomizers. The finite-volume code used is a three-dimensional, orthogonal, two-phase, Lagrangian-tracking, transient code. It contains submodels for the secondary breakup of droplets and for collisions. The effect of them chosen initial drop size distribution on the predicted fully developed spray characteristics is investigated. The optimum initial conditions are determined by making comparisons with published experimental data. It is found that to obtain a realistic model, a range of drop sizes needs to be introduced. This range can be represented by a truncated Rosin-Rammler distribution discretized into 20 size classes. Each initial distribution can be characterized by the maximum, minimum, and Rosin-Rammler mean diameters. Relations are developed for these diameters as a function of the operating parameters. This work demonstrates that, to model a solid-cone spray accurately, the microscopic processes occurring within it, such as secondary breakup,need to be accounted for.