Studies with orgonotypic culture of ventral spinal cord revealed that bombesin at 10(-4) to 10(-12) M exerts a marked growth-stimulating effect. The presence of bombesin, the neuritic extension of ventral spinal cord exceeds control values 1.5-4.8 times. The growth zone of spinal cord explants increases in the bombesin treated cultures. The possible mechanism of trophic effect of bombesin on ventral cord was briefly discussed.