The effects of six different methods for producing infantile malnutrition in rats upon brain lipid composition at 20 days of age were examined. The methods for producing malnutrition were: (1) large litters were fostered on the dams; (2) dams were fed a low-protein diet; (3) dams were fed an inadequate amount of a good quality diet; (4) pups were removed from the dams for half of each day and kept with a nonlactating female; (5) pups were removed from the dams for half of each day and kept in an incubator; (6) 7 of each dam's 12 teats were destroyed. Although total amounts of lipid were reduced in proportion to the reduction in brain weight by all of the methods, the methods varied as to the lipid components affected and in the extent of the deficits. We conclude that part of the lack of agreement between studies in this area of research is due to the variety in the methods used to produce malnutrition.