Advances in adaptive optics (AO) systems are necessary to achieve optical performance that is suitable for future extremely large telescopes (ELTs). Accurate simulation of system performance during the design process is essential. We detail the current implementation and near-term development plans for a coarse-grain parallel code for simulations of multiconjugate adaptive optics (MCAO). Included is a summary of the simulation"s computationally intensive mathematical subroutines and the associated scaling laws that quantify the size of the computational burden as a function of the simulation parameters. The current state of three different approaches to parallelizing the original serial code is outlined, and the timing results of all three approaches are demonstrated. The first approach, coarse-grained parallelization of the atmospheric propagations, divides the tasks of propagating wavefronts through the atmosphere among a group of processors. The second method of parallelization, fine-grained parallelization of the individual wavefront propagations, is then introduced. Finally, a technique for computing the wavefront reconstructions is analyzed. A parallel version of the block-symmetric Gauss-Seidel smoother, used in the conjugate-gradients reconstructor with multigrid-solver preconditioning, has been implemented. The timing results demonstrate that this is currently the fastest known full-featured, operational multiconjugate adaptive optics simulation.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.