This paper describes the application of a Parallel Genetic Algorithm that solves the weekly timetable construction problem for elementary schools. Timetable construction is NP-complete and highly constrained problem, and therefore represents a computationally intensive task. A Parallel Genetic Algorithm (PGA) is proposed with specific methods for chromosome representation and fitness evaluation, and specific recombination and mutation operators. The proposed solution uses a coarse grained PGA, which is suitable for execution on a Beowulf cluster. Experimental results are provided, with a comparison of serial and parallel execution times for the same algorithm.