LASPack is a package for solving large sparse systems of linear equations like those which arise from discretization of partial differential equations. It contains classical as well as selected state-of-the-art algorithms which are commonly used for large sparse systems such as CG-like methods for non-symmetric systems (CGN, GMRES, BiCG, QMR, CGS, and BiCGStab) and multilevel methods such as multigrid and conjugate gradient method preconditioned by multigrid and BPX preconditioners. LASPack is written in ANSI C and is thus largely portable. Postscript and HTML version of the reference manual are included.