We evaluated the effect of various microbial inoculants (Lallemand Animal Nutrition, Milwaukee, WI) on the fermentation and aerobic stability of corn silage. Corn silage (33% DM) was untreated (UN), treated with Lactobacillus buchneri 40788 (LB; 150,000 cfu/g of fresh forage wt.), treated with L. hilgardii 4785 (LH; 150,000 cfu/g), treated with LB + LH (LBLH; 150,000 cfu of each/g), or treated with LB500 (LBC; L. buchneri 400,000 and Pediococcus pentosaceus 100,000 cfu/g of fresh material). Five individually replicated lab silos (7.5 L) for each treatment were packed (208 kg DM/m³) and ensiled for 34 and 99 d between 21 and 23°C before testing for aerobic stability (ASb, h before a 2°C increase above baseline after exposure to air at 21°C.). An additional set of silos containing UN, LBLH, and LBC silages were prepared and subjected to ASb at a higher temperature of 29°C at 99 d. Data were analyzed using the Fit Model in JMP (SAS Institute Inc., Cary, NC) as a 5 × 2 factorial arrangement of treatments with the main effects of treatment, day, and their interaction. Lactic acid was higher (P < 0.01) in LH silages (6.11%) compared with LBLH and LBC silages, but similar to UN and LB silages at 99 d. Concentrations of acetic acid were numerically highest for LBLH (1.71%) of all treatments and lowest for UN (1.25%) and LB (1.22%). After 99 d, concentrations of 1,2-propanediol were higher (P < 0.01) in inoculated silages (0.77 to 1.12%) compared with UN (0.04%). At 34 d, silage treated with LBLH had the highest ASb (127 h, P < 0.01) compared with all other treatments. Treatment with LBC (87 h) also was more stable than UN (36 h), LB (44 h) and LH (49 h). At 99 d, ASb (P < 0.01) was higher in all inoculated silages (mean >360 h) compared with UN (79 h). When silages were exposed to the higher temperature during aerobic spoilage, treatment with LBLH and LBC had lower ASb than when spoiled at the cooler temperature but they were still markedly more stable than UN (P < 0.001). These data suggest that combining LB and LH results in synergistic effects on stimulating ASb after a relatively short time of ensiling.