With the current economic and political instability in Ukraine, children's health is most certainly the best indicator of socioeconomic development within the country and its different regions. This article analyses the socio-economic and environmental determinants of a child’s health in a big city (using the example of Lviv, a city in Ukraine). The demographic indicators of the child population of the city of Lviv and the reasons for mortality were traced; the structure of children’s diseases was analyzed; the factors affecting children’s health potential (such as local budget expenditures on health care, the level of average nominal wages, the ecological situation in the region) were studied. Published and non-published statistical data from the Main Statistical Department of Lviv Region, Lviv City Council were used. Specific consumer behavior among randomly selected Lviv households with children aged between 0-14 years was studied by using a special survey. Research results show the links between socio-economic and ecological factors (local budget expenditures on health care, the level of average nominal wages, the ecological indices in the region), and child mortality. The limited capacity of parents to satisfy the basic needs of households and complete lack, or limitation, of time that parents spend with their children undoubtedly influences the potential of children’s health in a destructive way.