The present study aimed to evaluate the effects of chitosan instead of microbial inoculants on fermentation profile, losses, chemical composition, in vitro degradation, and aerobic stability of sugarcane silage (SS). Forty experimental silos (PVC tubes with 28 cm i.d., 25 cm height) were used in a randomized block design to evaluate the following treatments: (I) Control (CON): SS with no additive; (II) LB: SS ensiled with 5.0 × 105 colony forming units (CFU) of Lactobacillus buchneri (NCIM 40788)/g as-fed; (III) LPPA: SS ensiled with 1.6 × 105 CFU of L. plantarum and 1.6 × 105 CFU of Pediococcus acidilactici/g as-fed; and (IV) Chitosan (CHI): SS ensiled with 6 g/kg dry matter (DM) of chitosan. Microbial inoculation of SS reduced (P ≤ 0.05) silage pH relative to CON and CHI treatment. The LPPA decreased ammonia-nitrogen and LB decreased (P ≤ 0.05) ethanol content and increased acetic acid content relative to other treatments. The LPPA-silos had higher (P ≤ 0.05) gas losses and lower (P ≤ 0.05) DM recovery than other treatment silos. Consequently, LPPA reduced (P ≤ 0.05) DM and non-fibre carbohydrates and increased (P ≤ 0.05) neutral detergent fibre (NDF) silage content compared to other treatments. Treatments did not affect (P ≥ 0.212) DM and NDF in vitro degradation and silage pH after aerobic exposure. However, LB reduced silage temperature after aerobic exposure. Thus, LB reduces alcoholic fermentation and improves SS aerobic stability. Inoculation of LPPA reduces DM recovery and negatively affects SS chemical composition. Although CHI positively affects SS conservation relative to CON, it shows higher gas losses and decreased SS temperature after aerobic exposure compared to LB.