The study investigated the impact of fermented cottonseed meal (FCSM) on growth performance, immunity and antioxidant properties, nutrient digestibility, and gut microbiota of weaned piglets by replacing soybean meal with FCSM in the diet. The experimental piglets were fed with either the soybean meal diet (SBM group) or fermented cottonseed meal diet (FCSM group) for 14days after weaning. The digestibility of dry matter (DM), organic matter (OM), crude protein (CP), gross energy (GE), amino acids and nitrogen was higher in the FCSM diet than those in the SBM diet (p