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Gastrointestinal ontogenetic studies constitute one of the basic and important investigations related to the nutrition of aquatic animals. In this investigation, specimens of the western white shrimp (Litopenaeus vannamei) at different developmental stages (from nauplius 1 to postlarvae 120) were assayed for the activities of digestive enzymes. According to the results, at all developmental stages, trypsin, amylase, and lipase enzymes were found to be active. In addition, the peak activities of all enzymes were revealed to occur during the late zoea larval stages (Z3). On the other hand, minimum activities were observed to occur at metamorphosis. During the postlarval developmental stages, amylase and lipase activities increased steadily, whereas the trypsin activity was more or less constant up to the eighteenth week. In conclusion, ontogenetic change in digestive enzyme activity may reflect either a developmentally cued change in enzyme synthesis or a secondary effect of change in the function and relative size of the midgut during its differentiation.