Owners often perform financial planning for individual projects and portfolios based on pre-defined budgetary periods. In principle, the owners need to balance the cash-out, which represents the contractors’ payments during the defined budgetary periods, with the cash-in, which represents the constrained budget. The achievement of the sought balance entails rescheduling of projects’ activities, which predominantly causes delays in projects’ completion. This paper formulates a model to simultaneously schedule multiple projects within portfolios under the constrained budget during budgetary periods and applies the multi-objective optimization to minimize delays of the individual projects. A Pareto front is presented, which offers a set of solutions, each of which involves optimized schedules of the individual projects. The multi-objective optimization algorithms of SPEA-II and NSGA-II were used to solve a case portfolio of two projects.