A crossed projection from the red nucleus to the cerebellar cortex in the cat has been demonstrated by means of retrograde transport of the wheat germ agglutinin-horseradish peroxidase complex. The majority of projecting neurons are situated in the rostral part of the red nucleus and have a maximum diameter of more than 20 microns. The findings indicate that rubrocerebellar fibers terminate in intermediate parts of the anterior and posterior cerebellar cortical lobes.