Previous studies have been shown algaroba (Prosopis juliflora) flour efficiency in tissue production in young Wistar rats as well as in undernourished animals. The effect of algaroba flour on pregnancy and lactation phases in Wistar rats were verified. It was evidenced that the interference of algaroba protein quality during pregnancy appears mainly in maternal organism in benefice to the breed, regarding the corporal weight gain, lipids and proteins compositions. The interference of algaroba protein quality was evidenced during the lactation, causing a depletion in the maternal organism, without ana equivalent sequel in the breed, which had its development damaged during the mix-feeding phase. However, algaroba flour was able to maintain pregnancy and also maintain the milk feeding even in adverse conditions without causing mortality or cannibalism, a phenomenon usually described in literature, during hypoproteic diet administration