This study evaluated two treatments based on addition of two commercial microbial inoculants of lactic acid-producing bacteria (LAPB), one of the homolactic type (HOT) and the other a combination of homolatic with heterolactic bacteria (HHT), plus a control treatment without inoculation (CNT), on the fermentative characteristics of tropical maize in micro-silos and aerobic stability (AS) of the resulting silage. The fermentative characteristics were determined in triplicate samples taken at various lengths of fermentation (15, 30, 58 and 90 d), which were analyzed for pH, concentration of organic acids and NHL. To evaluate AS, changes in pH and temperature of the silage were monitored during five days of exposure to air. No significant differences were found among treatments in any of the fermentation characteristics studied. HOT resulted in the numerically lowest average pH (4.23) and the highest average percentage content of lactic acid (2.18), followed by HHT (4.28 and 2.11) and CNT (4.32 and 1.94), respectively. Also, regarding indicators of AS there were no significant differences among treatments, but numerically the average pH of exposed HOT silage was lower (5.30 vs 5.43 the average value of both HHT and CNT) and there was a trend (P <0.15) toward lower average temperature (°C ) in favor of HHT (29.61 vs. 30.26 and 30.28 for HOT and CNT silages). In general, the use of LAPB inoculants in tropical maize silage did not result in large differences relative to non-inoculated silage in the variables under study regarding fermentation characteristics and AS.