Barker's "fetal origin hypothesis" advocates that the diseases in later life originate through adaptations that fetus makes when it is undernourished. These adaptations, whether cardiovascular, metabolic, or endocrine, permanently change the structure, and functions of the body, and pave the road to chronic killer diseases in later life, such as; coronary heart diseases, related disorders, stroke, diabetes, and hypertension. The main objective of the study, both prospective, and retrospective, covering the subjects from 0 to 1 year, and 3 to 15 years, respectively, is to test the Barker "fetal origin hypothesis" that nutrition in early life does influence the disease pattern in later life. The research is specifically designed to study the relationship between infant body size, placental weight, blood pressure, and lipid profile in late infancy; and whether or not the relationship between high blood pressure, and low birthweight is initiated in uterus, or during the infancy. The prospective studies were carried out in Prince Salman Bin Abdulaziz Hospital in Riyadh, KSA. The sampling was performed systematically. Every fifth child born in the delivery room was selected in the obstetric ward. A total of 1026 neonates were included in the prospective studies. The retrospective studies were conducted in Deraya Primary Health Care Centre, and data were collected from the medical record department, which included 1505 subjects, aged 3 to 15 years. The babies with major congenital malformations were excluded both studies included questionnaires, anthropometric measurements, and critical evaluation of haematological and biochemical parameters. The data collected, both prospective and retrospective and retrospective studies, were categorised, analysed, and statistically interpreted by using the Statistical Package for Social Science SPSS/PC+V9.0. Normal distributions of data were confirmed by using the Kolmogorow-Smirnow Test. In all cases, significance was assumed at P < 0.05. The major findings do support Barker's epidemiological data, and evidences. Although, it is still somewhat too early, and premature to confirm these findings, due to the length of period covered, the data presented, both prospective and retrospective, do point out, and lead to the following major conclusions: Chronic diseases are being imprinted "Programmed" in feto-placental unit during pregnancy, and infancy, there is indeed a strong association between birthweight, especially, low birthweight, and placental weight, blood pressure, lipid metabolism in early infancy, and in childhood. Low birthweight, <2500gms is strongly associated with elevated systolic blood pressure, and low birthweight infants, if survived, are predisposed to inevitable disabilities of all kinds, and chronic diseases in later life.