Perinatal undernutrition impairs maturational events in the development of the brain, resulting in a variety of brain dysfunctions, which affect cognitive functions. This study investigated the effects of pre- and post-natal undernutrition (diet: 8% protein; control group: 25% protein) on some glutamatergic and behavioral parameters of 21-day-old rats. In the cerebral cortex, undernutrition reduced the Na-independent [(3)H]Glutamate binding in cellular membranes and [(3)H]Glutamate vesicular uptake, without affecting the [(3)H]Glutamate uptake by slices preparation. Behavioral parameters were affected, showing a strong amnesic effect both in the short- and long-term memory of inhibitory avoidance tasks, and a significant reduction in the number of crossings in an open field. The effects of perinatal undernutrition in 21-day-old rats, which alter some glutamatergic parameters may be related to the impairment of memory in certain behavioral tasks.