This study was conducted to investigate effects of brain-derived neurotrophic factor on the neurite growth and the survival rate of antennal lobe neurons in vitro, and secretion of brain-derived neurotrophic factor-like neuropeptide from brain into hemolymph in the silk moth, Bombyx mori. In primary culture of antennal lobe neurons with brain-derived neurotrophic factor, it promoted both a neurite extension of putative antennal lobe projection neurons and an outgrowth of branches from principal neurites of putative antennal interneurons with significance (p<0.05). Brain-derived neurotrophic factor also increased significantly a survival rate of antennal lobe neurons (p<0.05). Results from immunolabeling of brain and retrocerebral complex, and ELISA assay of hemolymph showed that brain-derived neurotrophic factor-like neuropeptide was synthesized by both median and lateral neurosecretory cells of brain, then transported to corpora allata for storage, and finally secreted into hemolymph for action. These results will provide valuable information for differentiation of invertebrate brain neurons with brain-derived neurotrophic factor.