Aims: Prenatal and early life influences are important in the development of childhood cognitive abilities. Birth weight may be seen as a marker of intrauterine nutrition and has been shown to be correlated with intelligence in childhood. The aims of this study are to investigate if there is a relationship between cognitive abilities at age 11 and birth weight once other potentially confounding variables have been accounted for. Methods: Retrospective cohort study based on birth records from Bellshill Maternity Hospital, Lanarkshire from 1936, and cognitive abilities as measured by the Moray House Test (MHT) employed in the Scottish Mental Survey of 1947. Data was collected for 1327 births of which 729 cases were employed to assess the relationship between age 11cognition and birth weight. Other relevant information from birth records and birth certificates were used to control for potentially confounding variables and to assess their relationship with intelligence at age 11. Results: No association was found between birth weight and cognitive abilities (r=-.011, p=.784, 95% CI [-.094, .069]), even when gestational length was considered. There was, however, a significant relationship between social class and MHT score (F (6, 703) = 3.276, p= .003, η²=.027). There was also a significant association between birth order and intelligence (r= -.160, p=.001, 95% CI [-.234, -.086]). Conclusions: These results indicate that the socioeconomic environment a child develops in and their position in their family may influence childhood cognition. Low, normal or high birth weight was not found to be an important factor in the development of childhood cognition in this sample.