This study examined the effects of supplementation of dietary sodium selenite (SS) and sodium enriched alga Chlorella (SCH) on growth performance, selenium concentration in breast meat and excreta, activity of glutathione peroxidase (GSH-Px) in meat, andoxidative stability of meat in broilers. Broiler cockerels were allotted to 3 dietary treatments. The basal diet was supplemented with 0 (control) or 0.3 mg/kg Se from SS or SCH. Dietary supplementation with SCH increased body weight. The breast muscleSe concentration was increased by SCH supplementation, but not by SS supplementation. The concentration of Se in excreta was highest in the SS group. The activity of GSH-Px in breast meat was significant in all treatments. The inclusion of SCH in the diet enhanced the oxidative stability of meat.