Neuronal numbers in the neonatal rat superior cervical ganglion were estimated from counts made on paraffin wax sections stained with cresyl violet. The raw data were separately processed in accordance with the correction procedures of Abercrombie (1946) and of Hendry (1976). The results do not support the view that there is histogenic neuronal loss during the first 30 days post-partum. Figures corrected by the Abercrombie method indicated that the neuronal population is held stable throughout the first month of neonatal life at a level of about 35000 neurons. On the other hand, when the data was corrected by Hendry's method, the population appears to increase from less than 20000 to about 45000 neurons in the first week, and is then held at that level until the end of the study period. Moreover, histochemical studies using the acid-phosphatase reaction have previously indicated that there is little or no cell degeneration during this period.