Abstract This study explores the impact of chitosan nanoparticles (CNP) on the performance, nutrient digestibility, blood biochemical, immunity, microbial load, carcass traits and meat attributes of broilers. A total of 200 7-day-old Cobb chicks were distributed to four groups, each replicated five times, with ten birds in each replicate. The experimental diets were as follows: First group fed basal diet only (control); 2nd, 3rd and 4th groups received a basal diet supplemented with 0.2, 0.3 and 0.4 g CNP/kg of feed, respectively. Results showed that the body weight (BW) and body weight gain (BWG) significantly improved (P < 0.05) in the birds belonging to the 0.4 CNP group compared to the other groups. The best feed efficiency (FCR) was found in the group supplemented with a 0.4 g CNP/kg diet. The digestibility coefficients for dry matter (DM), and crude protein (CP) were significantly higher, and ether extract (EE) was significantly lower in the 0.4 g CNP/kg group than in other groups (P< 0.05). Broiler birds of the 0.4 CNP group had significantly (P< 0.05) reduced serum cholesterol, AST, and ALT levels. The humoral immunity (increased serum IgG and IgM levels) tended to improve in birds fed 0.3 and 0.4 g CNP/kg of feed. Compared to the control, total bacterial load and coliform count decreased significantly (P< 0.05) by supplementing 0.4 g CNP in the diet. The dressing weight, breast weight and abdominal fat % were altered in birds receiving dietary 0.4 g CNP/kg. The treatment with CNP at 0.4 g/kg feed enhanced the broiler meat quality by increasing the values for water holding capacity (WHC), ABTS [2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)], DPPH (2,2-Diphenyl-1-picrylhydrazyl) while reducing the thiobarbituric acid reactive substances (TBARS) value. Based on the results above, it could be concluded that CNP supplementation at 0.4 g/kg is recommended as a beneficial feed additive for broiler chickens.