This study was conducted to determine the effect of heat-killed Lactobacillus plantarum strain L-137 (HK L-137) on growth performance and immune response of white leg shrimp Litopenaeus vannamei. Three different supplemental amounts of 0.1 g of LP20 (which consists of 20% HK L-137) kg^-1, 10 g β-glucan kg^-1 and 0.05 g LP20+ 5 g β-glucan kg^-1 were used. These amounts were added to a commercial diet (control diet). Triplicates were done for each dietary treatment. Initial shrimp (PL12) were stocked in re-circulation 2 m³ tanks at a stocking density of 300 individual per tank, and were tested with these respective diets for 90 days period. Growth performance, survival rate and immune response were determined monthly or so. Formalin stress test and skin color evaluation were tested at the end of the study. The results showed that survival and growth rates of shrimp fed with feed supplemental LP20 grew significantly (PVibrio parahemolyticus challenges, were increased significantly (P