Frontal cortical projections from the rat suprageniculate nucleus (SG) were investigated by an anterograde tracing using Phaseolus vulgaris-leucoagglutinin (PHA-L). After PHA-L injection into the SG, labeled terminals were found in the frontal and temporal cortical regions. Labeled terminals in the frontal cortex were almost exclusively localized in the medial agranular area, and those in the temporal cortex were mainly localized in the primary and associational auditory areas. The labeled terminals in cortices were distributed predominantly in layers I, III and IV. The results suggest that ascending information through the SG projects to the medial agranular area in the frontal cortex as well as to the temporal cortex.