—Production of congenital Vitamin B6 (pyridoxine) deficiency in the neonatal rat is reported. Maternal pyridoxine deficiency resulted in pups with retarded neurological development and in some cases, convulsions. Litters were analysed in the neonatal period for the following: pyridoxal 5′‐phosphate and glutamic decarboxylase in whole brain, glutamic‐oxalacetic and glutamic‐pyruric transaminases in plasma and erythrocytes together with concentration of haemoglobin. The biochemical determinations confirm the existence of pyridoxine deficiency at birth. Copyright © 1969, Wiley Blackwell. All rights reserved