A quantitative comparison was made of the population of L5 dorsal root ganglion neurons that bind choleragenoid and the population of neurons labelled by RT97, an anti-neurofilament antibody, SSEA3, an antibody to a globoseries carbohydrate group and 1B2, an antibody to a lactoseries carbohydrate group. Neurons with choleragenoid binding formed a population of 37% of all the cells and 94% of these were also immunoreactive to RT97. The choleragenoid-and RT97-positive groups of cells showed the same size distribution. Two small populations of cells existed which were choleragenoid negative/RT97 positive and choleragenoid positive/RT97 negative. SSEA3 immunoreactivity was found in 8% of the dorsal root ganglion neurons which were of all sizes. The 1B2 immunoreactivity was found in 32% of the dorsal root ganglion cells, the majority of which were in the small size range. More than half of the SSEA3-positive cells but only a few of the 1B2-positive neurons were labelled for choleragenoid. These results demonstrate that choleragenoid labels the majority of the light (RT97-positive) cell population and that light cells unlabelled by choleragenoid are small in number and spread across a wide size range.