The effects of three intra-row spacings (20, 24 and 28 cm) with inter-row spacing of 70 cm and seed inoculation with plant-growth-promoting bacteria (PGPB) [(Azotobacter chroococum, Azotobacter vineland, Bacillus megaterium and Bacillus licheniformis)] were investigated on stem diameter (SD), stem lodging (SL), percentage of barren plants (PBP), grain yield (GY) and rain-use efficiency (RUE) in maize hybrid Dijamant 6 in the province of Vojvodina, Northern Serbia in 2006, 2007 and 2008. The highest SD and GY and the lowest SL and PBP were recorded in favorable climatic conditions in 2006. The lowest RUE was recorded in 2008 (unfavorable climatic conditions). The lowest SD and RUE and the highest SL, PBP and GY were obtained at the smallest spacing between plants in a row (20 cm). Seed inoculation significantly increased SD, GY and RUE, and SL and PBP significantly decreased. Generally, in Northern Serbia and similar ecological regions, treatment using 20 cm intra-row spacing (plant density of 71 429 plants ha^-1) and seed inoculation could be recommended to improve stem lodging resistance, decrease the number of barren plants and increase grain yield. To reduce yield losses in high crop densities, farmers should adopt appropriate crop management practices such as inoculation of seed with bio-fertilizer.