Dissociated cells from 5- to 12-day-old chick embryo cerebral hemispheres were cultivated in polylysine-coated plastic Petri dishes. The polylysine substrate was observed to be favorable for the growth of neuronal cells, whereas glioblast proliferation was inhibited. The optimal conditions for the production of a predominantly neuronal culture were to use cerebral hemispheres from 7-day-old chick embryos, to dissociate the brain tissue mechanically and to seed the cells at a concentration range between 1.5 and 5 × 106 cells/ml. The cultures were observed by phase contrast microscopy. Most cells grew fibers and differentiated into bipolar and multipolar neurons. These neurons were stained by thionine, which demonstrated the presence of Nissl bodies. The silver impregnation revealed the presence of neurofibrils within the nerve fibers. Acetylcholinesterase was found to be present in the neuronal cells, but absent in the glioblasts. Under our culture conditions the neurons survived for 10–12 days. This system should allow further studies on the effects of growth factors on the differentiation of isolated neurons as well as investigations on neuron-glial interrelationship.