Two consecutive green house experiments were carried out to examine the effect of Azospirillum spp. inoculation on growth, nitrogen and phosphorus accumulation in maize plants grown in pots. There were eight treatments including an uninoculated control and Azospirillum strains OAD-3, OAD-9, AZ-22, AZ-8, AZ-9, Azospirillum brasilense BR-11001 and Azospirillum lipoferum BR-11080. The inoculated plants showed higher values in each of the following measurements; plant height, total dry mass and nitrogen and phosphorus accumulation in shoot when compared to the uninoculated control plants in two consecutive experiments conducted in the same soil. Among Azospirillum strains, Azospirillum sp. OAD-3 inoculated plants showed higher nitrogen accumulation by 44.5% and 45.1%, total dry mass by 48.6% and 66.9% in two consecutive experiments respectively. The nitrogen concentration in the maize plants was not changed significantly in the first experiment, however it increased significantly in the second experiment due to Azospirillum inoculation. In addition, Azospirillum sp. OAD-9 and A. brasilense BR-11001 also proved to be effective with respect to total dry mass, total nitrogen accumulation and total phosphorus accumulation. The nitrogen concentrations in maize plants were increased in the second experiment due to Azospirillum inoculation.