Most receptive fields of neurons in the visual cortex (area 17) of rats could be mapped with moving and stationary stimuli. Neurons were most effectively driven by moving stimuli. They were classified s motion (37 per cent), orientation (11 per cent), or direction selective (4 per cent) and indefinite cells (41 per cent). Many cells had only a weak response to stationary stimuli: however, pure "on", "off" or "on-off" receptive fields were found for some neurons; others were of the complex type with mixed response regions in the receptive field. Receptive field sizes were usually quite large (range of the major receptive field axes for the most common class of cells-motion selective-was 15°-50°) as expected considering the sizes of retinal ganglion and LGN cell receptive fields as found in the rat by other investigators.