<p>Background: The developmental origin theory of coronary heart disease proposes that undernutrition in utero permanently changes body functions and metabolism leading to an increased risk of coronary artery diseases (CAD) in adult life. Some studies support this theory but others suggest that birth weight (BW) is not a major risk factor for cardiovascular diseases. Gender differences concerning the association between BW and risk factors for CAD have been reported in some studies but not in others.</p> <p>In this paper we have analyzed the effect of gender and diabetes on the relationship between BW and CAD in the White population of Rome.</p> <p>Material and Methods: 226 subjects admitted to the Hospital for non fatal CAD from the White population of Rome were studied. 395 consecutive newborn infants studied in the same population in the years 1968-1972 were considered for comparison.</p> <p>Results: Among subjects with CAD, reliable information on BW was obtained in 127 subjects. The distribution of BW in CAD depends on gender (p=0.009). In females with CAD there is a tendency toward low BW, while in males with CAD there is a tendency toward high BW. These associations are very marked in non-diabetic subjects with CAD (p=.001), while no significant association is observed in diabetic subjects (p=0.557).</p> <p>Conclusion: Our data confirm the association between BW and CAD and suggest that the association depends on gender and is influenced by diabetes.</p