In this paper the resource-constrained project scheduling problem with mult
iple execution modes for each activity and the makespan as the minimization
criterion is considered. A simulated annealing approach to solve this prob
lem is presented. The feasible solution representation is based on a preced
ence feasible list of activities and a mode assignment. A comprehensive com
putational experiment is described, performed on a set of standard test pro
blems constructed by the ProGen project generator. The results are analyzed
and discussed and some final remarks are included.