SparSol: Sparse linear systems solver. SparSol is a software package intended for preconditioned iterative solution of large sparse linear systems. It includes a number of iterative methods, preconditioners, scaling and reordering algorithms allowing one to choose the optimal combination of algorithms for a particular problem. The paper briefly describes the implemented algorithms and numerically compares the performance of SparSol with that of several popular, freely available software packages using test systems arising from hydrocarbon reservoir simulations.