his study was conducted to investigate the appropriate processing conditions for solid-statefermented soybean meal (FSBM) using a mixed starter culture ofStreptococcus thermophilus,Bacillus subtilisMA139, andSaccharomyces cerevisae(Exp. 1), and determine the effect ofFSBM (produced with appropriate conditions) as a partial replacement for soybean meal(SBM) on growth performance and nutrient digestibility of weanling pigs (Exp. 2). In Exp. 1,SBM was fermented using different processing conditions, including initial moisture content,incubation temperature and duration, sugar addition, protease supplementation, and neutralprotease to acid protease ratio. After fermentation, pH value and contents of crude protein,lactic acid, glycinin, andβ-conglycinin in FSBM were determined. Results showed that theappropriate incubation temperature for FSBM production was 401C. Greater initial moisturecontent (60%) and protease supplementation (0.3%) improved nutritional value. The suitableneutral protease to acid protease ratio was 3:1. Five days of incubation was sufficient forproduction of good quality FSBM. Addition of brown sugar did not affect the glycinin, andβ-conglycinin contents in FSBM. In Exp. 2, a total of 72 crossbred piglets (DurocLandraceLarge White) of an average weight of 8.9 kg were randomly allotted to 2 treatmentswith 6 replicate pens and 6 piglets per pen. Piglets were fed either a control diet with 24%SBM or a test diet with 6% FSBM added at the expense of SBM. Results from Exp. 2 showedthat replacing SBM with 6% FSBM improved average daily gain and average daily feed intake(Po0.05), while feed conversion ratio was unaltered. The nutrient digestibility and plasmaureaNconcentration in piglets on the FSBM diet were not different from those fed the SBMdiet. In conclusion, achieving a suitable incubation temperature, greater initial moisturecontent, and supplementing with protease are essential to obtain good quality FSBM. Feedinga diet containing 6% FSBM can result in greater growth performance in weanling pigs,implying that this new strategy has the potential to be used to produce solid-state FSBM