This book constitutes the thoroughly refereed post-conference proceedings of the Second Japanese Conference on Discrete and Computational Geometry, JCDCG8, held in Tokyo, Japan, in December 1999. The 27 revised full papers presented were carefully reviewed and selected for inclusion in the post-conference proceedings. Among the topics addressed are approximation, convex hulls, lattice computations, tilings, graph computations, Voronoi diagrams, clustering, graph drawing, diagram design, and illumination problems.