Abstract The aim of the present study was to investigate the effect of absorbent level and microbial inoculant on chemical compositions and fermentation characteristics of fermented poultry manure (FPM). In the first trial, the FPM was fermented using two levels of cassava solid waste as absorbent, consisted of 10% (AL10) and 30% (AL30). The best absorbent level to improve the quality of FPM was continued in the second trial. In the second trial, FPM was fermented using inoculant treatments following without inoculants (CON), Lactobacillus plantarum (LP) and multi-purpose microbes (MP). All fermentation was conducted for 14 d in 4 kg mini-silo with quadruplicate. In the first trial, AL30 had higher levels of dry matter and crude fiber but lower levels of crude protein, ether extract, and butyric acid content compared to AL10 (P<0.05). In the second trial, CON presented higher levels of dry matter, crude protein, and crude fiber, but lower levels of ether extract, nitrogen-free extract, pH, ammonia, and butyric acid compared to LP and MP (P<0.05). In conclusion, the present study found that FPM without inoculant at the 30% absorbent level resulted in higher nutrient composition and better fermentation characteristics compared to other treatments.