Infectious diseases are an ever important medical problem. Health Service reorganization, may contribute to further increase of the diseases. The aim of the study was the retrospective analysis of the incidence of selected infectious diseases in Wielkopolska and the comparison of the regional and national data. Incidence of infectious diseases in Wielkopolska in the scrutinized period was lower than the national one, except 1990 & 1992. The value of incidence for tuberculosis for Wielkopolska various from the national trend which decreases noticeably and significantly from 1997. No other permanent trends in the incidence of infectious diseases were observed throughout the analyzed period.