Bevelled glass microelectrodes were used to record spike potentials extracellularly from the ganglion cells of the rabbit retina. Good responses were obtained from the isolated retina or eye-cup preparation for at least 12 h. Using a contrast reversal stimulus, 63.8% of the units showed linear spatial summation (X-cells), and 21.0% showed nonlinear spatial summation (Y-cells). The X- and Y-cells in the rabbit retina had physiological properties similar to those in cat retina. Directionally selective cells (15.2%) responded poorly, if at all, to the contrast reversal stimulus.