Glucose excretion and dextrose: nitrogen ratios were measured following phlorizination in young fasting rats depleted of pyridoxine and in their pair-fed controls. The same determinations were also made in older and non-fasting animals following a period of 11 to 16 weeks on a sugar-free, pyridoxine-free ration. Pair-fed rats were again used as controls. No significant differences were found between groups. It is concluded that under the experimental conditions described, pyridoxine insufficiency does not exert a specific effect on gluconeogenesis.