Description: Marshmallow (Althea officinalis) is one of the important medicinal plants in Serbia. One of the bigest problem in growing of marshmallow is poor seeds germination. Rhyzospheric bacteria able to produced plant growth stimulating hormones can inpruve seed germinations and decreace seed infections with patogens. IAA production by Bacillus sp. Q3 strain estimate in this investigation ranged from 3.76-10.62 хgml-1. The application of soil bacteria as the antagonists to the growth of pathogenic fungi, indicated that IAA producing Bacillus sp. strain Q3 demonstrated not only a high level of antagonism towards the seed mycoflora, but significantly increased the germination rate of the marshmallow seed