This paper presents a new hybrid genetic algorithm used to solve a frequency assignment problem. The hybrid genetic algorithm presented in this paper uses two original mutation operators. The first mutation operator is based on a greedy algorithm and the second one on an original probabilistic tabu search. The results obtained by our algorithm are better than the best known results obtained by other methods like tabu search and hybrid genetic algorithm. Our results are validated in the field of radiobroadcasting and compared to the best existing solutions in this domain.