This study was conducted to examine the levels of infant mortality, its causes and determinants, and its differentials in selected slums of Calcutta Metropolis and Raipur in India. Data were gathered through interview of 2142 mothers who had experienced a live birth and/or death of an infant within the year prior to the survey. The study found that although the infant mortality rate (IMR) in the slums was quite high, it was lower compared to rural India. The study¿s finding underlines the importance of "urban residence" as a primary controlling factor of infant mortality. IMR was 1.5 times higher in the slums of Calcutta than in Raipur, indicating that infant death is far worse in the metropolis than in smaller cities. Although a number of individual-, household-, and slum-level factors played an explanatory role in infant mortality, differences in neighborhood environment contributed most significantly to the infant mortality differentials in the two slums. This study also found that mere literacy or low level of education is not an effective depressant of infant mortality.