Two field trials on rice plants (Oryza sativa) variety Giza 178 cultivated at El-Saw Agricultural Research Station were conducted in two successive seasons (2001 and 2002). Microbial inoculation with two strains of nitrogen fixers, namely Bacillus polympa and Azotobacter chroococcum as well as yeast strain (Saozharomyces cerevisiae) was applied. Effect of inoculation time (rice nursery and transplanting stages) was studied. Split plot with 4 replicates was designed. Plant height, number of productive tillers, panide length and weight were recorded. Grains and straw yields were also estimated. Nitrogen percent of grains and straw were determined. Microbial inoculation of nursery and transplanting stage revealed a significant effect on both yield and plant growth parameters in the presence of half and full recommended dose of nitrogen in comparison with other treatments. Similar response was detected with yeast inoculant except nitrogen percent of grains.