In this study a total of 29 Bacillus species isolated from the soil was analyzed using the agar diffusion method in terms of their general, inhibition effects to some test bacteria. It has been found that isolates are effective against Gram-positive and Gram-negative bacteria whereas their extensive inhibition effect is particularly against Gram-positive bacteria. On the other hand, B. cereus M15 strain has an inhibitory effect against both Gram-positive and Gram-negative bacteria. Furthermore some isolates are more effective against test bacteria when compared to some antibiotics. (C) 2005 Elsevier GmbH. All rights reserved.