This volume contains the proceedings of the Second International Workshop on Hybrid Systems: Computation and Control (HSCC'99) to be held March 29- 31, 1999, in the village Berg en Dal near Nijmegen, The Netherlands. The rst workshop of this series was held in April 1998 at the University of California at Berkeley. The series follows meetings that were initiated by Anil Nerode at Cornell University. The proceedings of those meetings were published in the Springer-Verlag LNCS Series, Volumes 736, 999, 1066, 1201, and 1273. The p- ceedings of the rst workshop of the new series was published in...