This study was designed to evaluate the survival of shrimp postlarvae under osmotic stress and its relation with the molt stage.Postlarvae used were in stages PL7 to PL17.Osmotic stress was tested during intermolt stage (IM), initial premuda (PrMI) and final premuda (PrMF), determining its effect on survival.For this analysis the development of PLs gill, individuals weight and water quality parameters were taken into acount.Thirty three treatments in triplicate consisting of 2 factors, moult stages (IM, PrMF and PrMI) and age of postlarvae (PL17 to PL7).The results show significant differences for the interaction molt stage and age.The highest survival was found at the intermolt stage (74.12%) from PL12.