The effects of <undernutrition> during early life on acetylcholinesterase (AChE) specific activity of <cerebellum>, <hippocampus> <hypothalamus> and <striatum> were examined in rehabilitated adults <rats>. Undernourished rats were raised by dams maintained on a <restricted food> scheme from pup birth to pup weaning. The offspring were maintained on a restricted food schedule until day 38 when they started to have free access to food until 70-80 days of age. Control rats were raised by dams which had free access tofood. The results showed that early malnutrition caused a significant increase in AChE specific activity in cerebellum (about 20%), striatum (about 40%), and hypothalamus (about 30%). No changes were found in the hippocampus. Undernutrition caused a significant increase in Vmax when compared to the control group without changes in Km both in cerebellum and striatum. These results suggest that early undernutrition changes AChE concentration in cerebellum and striatum and does not affect the affinity of the enzyme for the substrate.