In humans, low birth weight is associated with nonfatal stroke, cardiovascular disease and diabetes at adulthood. The aim of this study was to investigate in rats the effect of early protein restriction, inducing low birth weight, on brain and endocrine pancreas vascularization at birth and to study if such alterations lasted until adulthood. Pregnant rats were fed either 20 or 8% protein isocaloric diets. Control newborns were nursed by their dams fed the 20% protein diet and low protein (LP) pups by dams fed either the 8 or 20% protein diet. The diets given during lactation were maintained until adulthood. The blood vessel density of cerebral cortex analyzed by morphometry in 3-d-old pups from dams fed the 8% protein diet was lower than in control (C). It remained lower at adulthood whether a LP or a C diet was given postnatally. Reduction of vascularization at adulthood induced by the LP diet limited to fetal life seems characteristic for the brain since vascularization of islets of Langerhans was reduced in neonates but normalized at adulthood by a C diet postnatally. Body and brain weights were lower in LP pups and adults. DNA concentration was lower in forebrain and higher in cerebellum in LP pups. In brain of LP adults, DNA, protein, cholesterol and phospholipid concentrations were tower and were restored at adulthood by a normal diet after birth. In conclusion, cerebral cortex of offspring exposed to a LP isocaloric diet during fetal development showed reduced vascularization which remained throughout life