The projection of the visual field onto the dorsal lateral geniculate nucleus (LGN) of the ferret was mapped electrophysiologically. The nucleus contains a single orderly map of the contralateral visual hemifield. The upper visual field is represented dorsally and rostrally in the nucleus; central fields are found in the medial and caudal sections of the LGN; and peripheral fields are represented most laterally. The ipsilateral eye is represented in laminae A1 and C1 up to eccentricities of 20-30 degrees. Lines of projection run perpendicular to the laminar borders. The ferret LGN resembles that of the cat rotated approximately 110 degrees clockwise in the sagittal plane, viewing the right nucleus from its lateral aspect; it differs from the cat in having a larger monocular segment.