Obesity is a disease on global level, it has a medical diagnosis stipulated in International Statistical Classification of Diseases and Related Health Problems. This disease heavily depends on his/her physical activity and this person everyday's routine. Body mass index measurement is one of the most simplest and therefore very widely used methods for measuring if some individual has disease called obesity. This index is calculated in a way that body mass of certain person expressed in kilograms is divided with square height of the same person expressed in meters, and person who has this index >30 kg/m2 has obesity. Beside the fact that physical activity is one of the major components of everyday's life, its one of most variable components of person's energy consumption and therefore it has enormous significance in body mass regulation. Low level of this activity is connected with obesity development as one of non-infectional diseases. According to various researches, physical activity reduces risk of development some other non-infectional diseases aside obesity. During the last decade or so, modern society institutions are trying to educate whole planet population aiming to prevent obesity to appear, through a popularization of physical acitivity as something positive for individual development of every person. Physical inactivity is a cause, and physical activity is a cure for many public health issues and problems. (18) Part of data collected through EHIS were used as a basis for research among working population of Koprivničko-križevačka county – if there is a correlation between physical activity and obesity. Results of this research show that hard labour results with normal body mass index for both sexes, that men which have this index normal percieve their health better than those who don't have it (and women are not percieving that this is connected), that women who use bicycle more than 4 days a week have normal body mass index and men have not. One of the challenges of modern society is to bring to every person consciousness that appropriate level of physical activity results with risk reduction of obesity development as one of the non-infectional diseases. It's not enough to promote only physical activity as something positive to every person, it has to be combined as a part of promotion of health life style, alongside with smoking and alcohol consumption reduction, among others.