The purpose of this study was to determine whether caffeine’s effects on the growing brain in suckling pups are modified by the nutritional status of the dams. Upon delivery, 8 randomly selected pups were assigned to each dam. They were divided into four groups; group 1 was fed a 20% protein diet as a control; group 2 was fed a 6% protein diet as a malnourished group; group 3 was pair-fed to group 1, but the 20% protein diet was supplemented with caffeine (2mg/l00g body weight of dams), and group 4 was pair-fed to group 2 with a 6% protein diet with caffeine. At day 15, pups were killed. Brains were removed, weighed and homogenized. Caffeine content of plasma, brain of the pups and maternal milk in groups 3 and 4 were determined. Brains were analyzed for zinc, alkaline phosphatase activity, DNA, protein, and cholesterol. Body weight and protein content of group 3 were greater than group 1 but the zinc contents and alkaline phosphatase activity of group 3 were less than group 1. DNA and cholesterol contents of group 4 were greater than group 2. Supplementation of caffeine to the maternal diet appeared to have various effects on the growing brains of the suckling pups. Caffeine’s effects and nutritional status are closely interrelated.