Aims: To investigate the potential antagonistic activity of Paenibacillus peoriae strain NRRL BD-62 against phytopathogenic micro-organisms and to determine the physiological and biochemical characteristics of the antimicrobial compound produced by this strain. Methods and Results: Strain NRRL BD-62 showed a broad inhibition spectrum with activity against various phytopathogenic bacteria and fungi. Physico-chemical characterization of the antimicrobial activity showed that it was stable during heat treatment and was retained even after autoclave at 121degreesC for 10 min. The compound was also stable after the treatment with organic solvents, hydrolytic enzymes and its activity was preserved at a wide range of pH. The partial purification carried out by Sephadex G25 gel filtration showed two profiles of inhibition against the indicator strains tested, suggesting at least two different substances with distinct molecular weight. Conclusions, Significance and Impact of the Study: This is the first report on the production of antimicrobial substances in P. peoriae. Besides the antimicrobial inhibition capability, the strain NRRL BD-62 is also able to effectively fix molecular nitrogen, and produce chitinases and proteases as well, suggesting that further studies should be addressed to use P. peoriae strain NRRL BD-62 as a plant growth promoter and/or as a biocontrol agent in field experiments.