The potential of water hyacinth leaf protein concentrate (WHLPC) as an alternative protein source to soybean meal in formulated diets for the white shrimp Litopenaeus vannamei (Boone) postlarvae, was assessed. Isonitrogenous and isolipidic diets were formulated containing 40% protein and 8% lipid. WHLPC replaced 0%, 25%, 50% and 75% of soybean meal protein in the formulated diets. Twenty postlarval Litopenaeus vannamei weighing 5.0 ± 0.00032 mg were randomly assigned to twelve 30‐L aquarium tanks and were fed experimental diets for 70 days. Results show that the overall biological performance of shrimp in terms of specific growth rate (SGR), protein efficiency ratio (PER), feed efficiency (FE) and survival in treatment receiving the 25% WHLPC replacement is comparable to that of the control diet. Replacement levels beyond 25% exhibited significant depression in terms of growth performance of the shrimp. Collectively, these findings indicate that WHLPC can replace 25% of soybean meal protein in the formulated diets of L. vannamei.