This investigation was carried out during 1996 and 1997 maize growing seasons at Gemmeiza Agricultural Research Station to evaluate the efficacy of some biocontrol agents, used as seed treatments, in controlling downy mildew disease of maize caused by P.sorghi under Egyptian condition. Field trials results have demonstrated that, downy mildew infection percentages were differed with the different seed treatments . Seed coating with the biocontrol agents was more effective than seed soaking with those agents during the two successive seasons. Bacillus subtilis used as seed coating was the most effective in reducing the disease infection percentage compared with the control. It exhibited 86.97 and 82.39% efficacy during 1996 and 1997 seasons, respectively. On the other hand, Trichoderma harzianum was the least one in this respect, where it gave only 11.05 and 3.78% efficacy in 1996 and 1997, respectively. No definite trend of infection due to seed soaking was found except with. Pseudomonas fleuroscence  isolate No. (2) used as  seed soaking which was effective with non-significant differences in controlling the disease comparing with the rest of the tested biocontrol agents. This treatment reduced the percentage of disease incidence from 56.8% and 53.20% to 47.07% and 40.36% during 1996 and 1997, respectively. There was no significant difference between treatments with Bacillus subtilis as seed coating and the recommended fungicide (Apron), in this respect.