Abstract 1. In the brains of worker honeybees ( Apis mellifera carnica) corresponding to different stages in the life span, we measured the content of GABA, glutamate, acetylcholine, eholine, norepinephrine, dopamine and serotonin. 2. The highest concentrations were found for GABA, glutamate and acetylcholine. 3. Biogenic amines occur in considerably lower concentrations in comparison to the above mentioned transmitters. 4. Age-correlated changes were found for different neuroactive substances. 5. GABA and glutamate show a well marked rise and fall of their concentrations with a maximum at day 10. 6. The results are discussed in comparison to other species and with respect to age polyethism of worker honeybees.