Fungicidal mixtures, comprising 1) a fungicidal Bacillus substilis strain with NRRL Accession No. B-21661, or a mutant of these strains having all the identifying characteristics of the respective strain, or a metabolite produced by the respective strain that exhibits activity against plant pathogenic fungi, and 2) at least one chemical compound II, selected from active heterocyclic compounds; in a synergistically effective amount, methods for controlling harmful fungi using compositions of components 1) and 2), the use of a component 1) with a component 2) for preparing such compositions, and also fungicidal agents and seed comprising such compositions.