Present paper is devoted to a problem of the analysis of medicoecological situation in large industrial city (by the example of Balakovo city of Saratov region). An object of such investigation is, first of all, the studying of correlation between pollution of the environment in the city and morbidity of citizens. In the current paper the GIS-method and some intermediate results of the analysis of medico-ecological situation in Balakovo are presented. Some features of input data processing are considered.