In human populations, patterns of disproportionate fetal growth are associated with cardiovascular disease in later life. Protein restriction of pregnant rats is known to impair fetal growth and is also associated with increased systolic blood pressure in later life. Growth of fetuses exposed to maternal low protein diets was found to be accelerated between day 14 and day 20 of gestation, but this growth appeared to falter in late gestation, resulting in low or normal birthweights. Placental growth was also accelerated by protein restriction. Day 20 fetuses from rats fed low protein diets were heavier but had proportionally smaller brains than did control fetuses. These animals were also longer in proportion to body mass. Between day 20 and full term (day 22), growth of the brain was spared at the expense of the trunk and at birth, pups exposed to low protein were short in relation to body mass. At weaning, rats exposed to low protein diets in utero had significantly higher systolic blood pressure relative to control animals. These data indicate that increased blood pressure in rats is linked to disproportionate patterns of growth in middle and late gestation.