This study was conducted to evaluate the effects of algal fucoidan and probiotic Bacillus subtilis on growth performance, blood metabolites and intestinal morphology in broiler chickens. A total of 250 one-day-old Ross 360 male broiler chickens were randomly distributed into 5 treatments (6 replication pens/treatment) and reared for 42 d. The 5 dietary treatments were as follow: 1) a corn-soybean meal basal diet (control treatment); 2) a basal diet supplemented with antibiotic oxytetracycline; 3) a basal diet supplemented with the prebiotic fucoidan; 4) a basal diet supplemented with a probiotic product containing Bacillus subtilis spores; and 5) a basal diet supplemented with both the prebiotic and probiotic (served as a synbiotic). Birds received antibiotic and probiotic exhibited greater body weight gain (about 5.42% and 4.80%, respectively) than control treatment. The percentage of thigh and abdominal fat in birds fed probiotic diet were lower compared to the antibiotic treatment. The use of fucoidan and probiotic resulted lower (P< 0.05) serum concentration of triglyceride than those of antibiotic treatment. Supplementing of synbiotic increased villus height and villus height to crypt depth ratio in the jejunum (P< 0.05). Present study revealed that supplementing of probiotics with fucoidan could be advised as an effective synbiotic, instead of antibiotics, to improve the performance and health of broiler chickens.