Abstract: The effect of inoculation of wheat (Triticum aestivum L.) with different microbial strains was studied under experimental field conditions. Seeds of two wheat varieties viz. WH711 and Raj3765 were inoculated either singly with microbial strains, namely Azotobacter chroococcum strain Mac27, Trichoderma viride, Pseudomonas strain P20, Bacillus strain SYB101 or seeds were co-inoculated with biomixture of Pseudomonas and Bacillus strains. Inoculation with Bacillus strain SYB101 showed maximum seed germination in both the varieties of wheat. Seed treatment of wheat with Bacillus strain SYB101 or their co-inoculation with Pseudomonas strain CP56 and Bacillus strain SB155 produced longer root and shoot length and also resulted in higher vigour index values over untreated control. Under field conditions, inoculation of the wheat variety WH711 with Bacillus strain SYB101 caused 32.6% increase in seed yield whereas inoculation of this strain on the other wheat variety Raj3765, caused 23.1% increase in seed yield in comparison to uninoculated control treatment. Inoculation with Azotobacter chroococcum showed only 7.4% increase in the variety Raj3765. Co-inoculation of Pseudomonas strain CP56 and Bacillus strain SB155 showed 23.3 and 19.4% increase in variety WH711 and variety Raj3765, respectively. Maximum enhancement in seed yield was obtained with Bacillus strain SYB101 and, therefore, this strain could be exploited for use as biofertilizer for improvement of wheat growth and seed yield under field conditions.