A study was conducted to evaluate the effects of dietary lentinan (LNT) on growth performance, nonspecific immunity and disease resistance to Aeromonas hydrophila in largemouth bass (Micropterus salmoides). Largemouth bass (initial weight: 10.31 ± 0.25 g) were divided into the CK, L1, L2, L3, L4 and L5 groups in triplicate and fed with diets containing LNT at 0%, 0.05%, 0.1%, 0.2%, 0.3% and 0.4% for eight weeks. Results showed that FBW, WGR, SGR and FE were significantly increased in the L3, L4 and L5 groups compared to the CK group. VSI, HSI, crude protein, crude fat and crude ash were similar among different treatment groups. Trypsin and lipase activities of intestinal tract were elevated in the L4 and L5 groups. The length of intestinal microvilli was increased in all experimental groups (P