The origin of divergent and non-divergent pathways from substantia nigra to the thalamus were studied in experiments on rats using retrograde axonal transport of luminescent tracers and horse-radish peroxidase. Two efferent projection systems are shown: the first--with divergence of axon collaterals to the caudato-putamen of both hemispheres, caudato-putamen and globus pallidus, caudato-putamen and nucleus accumbens, ipsilaterally; the second system is directed to the thalamus, and does not form axon collaterals to striatal structures.