Both anterograde and retrograde degeneration techniques were employed to investigate the cortical projections of the dorsal lateral geniculate, medial interlaminar and posterior nuclei of the thalamus. The dorsal lateral geniculate was found to project principally to cortical areas 17 and 18, with an additional, minor projection to the lateral bank of the middle suprasylvian gyrus; the projection from the medial interlaminar nucleus is considered to be restricted to area 18, while the posterior nucleus appears to have two major cortical projections, to respectively area 19 and the lateral bank of the suprasylvian gyrus.The projection from each thalamic visual nucleus to the respective subdivisions of visual cortex was found to be organised topographically such that anterior and posterior parts of the thalamic nucleus project to anterior and posterior parts respectively of the appropriate cortical areas. The cortical projection of the dorsal lateral geniculate is topographically organised in the medio-lateral dimension also, such that medial parts of the nucleus project to lateral area 17 and medial area 18, while lateral parts of the nucleus project to medial area 17 and lateral area 18; no information was obtained on the medio-lateral organisation of the projections from the medial interlaminar or posterior nuclei.No evidence was found of a projection from the dorsal lateral geniculate, medial interlaminar or posterior nuclei to the contralateral occipito-parietal cortex.