In the past, only meagre attempts were made to understand the complex behaviour of contraception in Madras City, covering only limited factors of the urban population. The present study tries to bridge the gap of knowledge related to the eligible couples and their contraceptive behaviour. It also puts greater emphasis on the study of slum population which generally lags behind in adopting family planning techniques. Since the population in the metropolitan city of Madras had started increasing at a much faster rate than the amenities offered to it, there was an urgent need for undertaking studies of determinants of family planning there.'