Extracts of culture of fungal taxa belonging to Chaetomiun sp., Guignardia mangiferae, Pestalotiopsis guepinii, Phomopsis sp., Physalospora sp., and sterile mycelium isolated as endophytes from leaves of members of the plant fafmilies Anacardiaceae, Leguminosae and Palmae, and seven different species of Penicillium isolated from insects were tested for their in vitro acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activity using Wllman´s colorimetric method adapted for thin layer chromotherapy. The results showed hig rate of cholinesterase inhibitory activity, with the best result being obtained with Penicillium extracts, indicating that they might represent a valuable source for pharmaceutical applications and are worthy of further study.