We investigated the effects of corn oil and perilla oil intake by rats during pregnancy and lactation on the fatty acids composition of plasma and brain of rat pups. Two groups of dams were fed either a corn oil diet (CD) or a perilla oil diet (PD) during their pregnancy and lactation. On days 8, 21 and 33 after birth, two pups each from the litters of all dams were killed and their blood and brain samples were collected. After weaning, the 46 and 60-d-old pups were dissected. On day 8 after birth, although the n -3 fatty acid in the plasma of the PD group was 3 times higher than that of the CD group, no significant difference in the brain was observed between the two groups. On day 1 after birth, no brain n -3 fatty acid composition in the pups from both groups was detected, but they increased with the pup′s growth. The n -6/ n -3 in pup′s brain of dams fed the CD and the PD was 1. 88 and 1. 74 on the day 8 after birth, and 1. 26 and 0. 93 on the day 60 after birth, respectively. Therefore, it was suggested that the fatty acid composition of the brain in pups remained constant while the dams were fed different oils during pregnancy and lactation.