Infant mortality in Imperial Germany started to decline in urban areas from the 1870s onwards, whereas national rates did not decrease before the beginning of the twentieth century. Therefore, key explanatory factors determining the levels and trends of infant mortality are investigated in an urban context. These include the decline of birth rates, the legitimacy status of infants, feeding practices, environmental conditions, and economic growth. Through a rising living standard and by creating a health-preserving environment, urban populations lost their traditional disadvantage in survival chances. This went so far that even high risk factors, such as the abandonment of breastfeeding, could be counterbalanced. In this sense, a study of past urban health conditions functions as a paradigm for the situation in industrialized societies.