Sumgayit is the third largest city in Azerbaijan, having a population 297 700 and is located approximately 30 km northwest of the capital city Baku on the Absheron Peninsula. In the late 1950s, Sumgayit was founded as a center for chemical and petrochemical industries. Discharges into the atmosphere and water reservoirs from 1970-1990 resulted in high environmental contamination. In 1992, the Azerbaijan Republic State Committee on Ecology declared Sumgayit an ecological disaster zone, although emissions have decreased significantly since 1990, as industrial production has declined. The paper describes the situation in the city and suggests the methods which can be used to identify the distribution and determinants of birth defects in Sumgait with a view to characterizing the contribution of past and present contamination to these risks.