AIM: The aim of the research is to determine according to the GOLD Classification of Smokers' Disease whether there are differences between the sexes in smoking time and it’s relation to housing in the urban or rural environment. This was the personal part of the research of the smoking co-morbidity and the risk of chronic obstructive pulmonary disease (COPD) development within the MARKO project. The ultimate goal was to establish the epidemiological characteristics of chronic diseases of the lower respiratory system (CDLRS) in the Split-Dalmatia County (SDC) in relation to the Republic of Croatia. MATERIAL AND METHODS: The personal research part of the final work was carried out in the form of a cross-sectional study on the principles of the MARKO project implemented in 2010-2011. There was 124 selected smokers aged 20-64, without previously established COPD and other conditions that significantly deviate from the healthy part of the population. The epidemiological features of the SDC are retrospective studies of mortality by CDLRS. In both parts of the final work a comparative epidemiological method was used. The standardization of mortality and mortality rates was done by a direct method according to the European Standard Population 2013 (ESP 2013). Statistical significance was calculated by the χ²-test, Student's t-test, with 95% CI (Confidence Interval), the significance of differences on the level of reliability P <0.05 or greater. THE RESULTS: Despite the fact that a sample of 124 current and ex-smokers tested by their family medicine practitioners and that this small, non-representative sample without a full-time control group it could be established according to GOLD classification that there is no significant difference between male and female gender or between urban and rural area for all respondents. However, in the analysis of the respondents divided by the length of smoking time up to and over 40 years in male sex and up to 30 and over 30 years in the female sex, statistically significant differences were found. There are no healthy smokers in both sexes at the time of the questioning of the City of Split with a higher smoking age, while the symptomatic smokers are statistically significantly higher (P <0.01). By the presence of comorbidity observed in 73 subjects for nine predetermined disease /states, hypertension and hyperlipidemia are leading ones. Statistically significantly higher proportion (%) of patients with no illness so called "Healthy smokers" were found in the rural population in the municipalities of 66.7% vs. 31.0% (χ²-test = 6.52, P <0.05). The subjects of both sexes of the City of Split had a statistically significantly higher proportion of all comorbidity than the inhabitants of the municipalities 92.9% vs. 66.7% (χ²-test = 14.26; P <0.001) as well as statistically significantly higher proportion of subjects with single disease (45.2%) compared to district respondents (8.3%) (χ²-test = 7.96; P <0.01). This difference is the result of higher share in male sex, while in the female gender there is no significant difference. Compared to the total population of the population aged 20-64 years in the smokers' risk of developing COPD, there is a statistically significant increase in the prevalence of hypertension and peptic syndrome. There is a statistically significant decrease in affective disorders, while there is no significant difference in diabetes mellitus, myocarditis, shingles and rheumatic diseases. The results of personal research are consistent with epidemiological considerations. Average annual mortality from CDLRS in SDC in the period 2007-2015 year 22.21 / 100.000 for both sexes is statistically significantly lower than the average annual mortality rate for Croatia 37.50 / 100.000, and especially from the average annual mortality rate of the continental counties of Croatia 41.77 / 100.000. CONCLUSION: From the results of the personal research, although without the results of the second phase of the research and the results of the epidemiological analysis of the mortality of CDLRS in the SDC, it can be conclusively and irrefutably state that tobacco smoking is the predominant cause of the disease and mortality of CDLRS and COPD itself. Despite the good results in the Republic of Croatia and even better in the SDC, much more can be achieved by working on primary prevention of CDLRS, which is a constant fight against tobacco smoke. All health professionals must participate in the coming years as soon as possible to reduce the share of smokers from one third to one quarter of the total population. A special place in these endeavors belongs to nurses who are educated and prepared for work in the community on the primary task of primary prevention of CDLRS and lung cancer.