The dietary, clinical and biochemical investigations reported in this paper revealed that the large majority of the subjects-pregnant women of the low socio-economic group in South India-underwent the nutritional stress of gestation without adequate preparation or protection either before or during pregnancy. The subjects suffered from varying degrees of calorie-protein deficiency and a large number showed manifestations of vitamin B complex deficiency and anaemia.Their nutritional status was possibly reflected in the high percentage of premature termination of pregnancy. Those babies born alive at term had a low average birth weight, nearly one-third of them weighing less than 2500 g at birth. It is suggested that these small-sized under-weight infants, even if they are physiologically and functionally mature and manage to live, probably possess very little nutritional reserves and become potential subjects for the development of nutritional deficiency and its consequences during the early months of life.