SUMMARY -Th e aim of the study was to investigate the unknown eff ect of air pollutants on the occurrence or deterioration of respiratory diseases in the area with a humid continental climate. Th is retrospective study included 5868 patients with respiratory symptomatology (upper respiratory tract infection (URTI), pneumonia, acute bronchitis, chronic obstructive pulmonary disease (COPD), and asthma) admitted to emergency department (ED). Th e number of patients, values of meteorological parameters (mean daily values of air temperature pressure and relative humidity) and concentrations of air pollution particles (≤10 μm (PM 10 ), ozone (O 3 ) and nitrogen dioxide (NO 2 )) were collected during a two-year ( July 2008 -June 2010) period. Th ere were 1839 (31.3%), 1712 (29.2%), 1313 (22.4%), 614 (10.5%) and 390 (6.6%) patients with pneumonia, COPD, URTI, acute bronchitis and asthma, respectively. Th e mean daily concentrations of NO 2 (25.9 (1.7-89.7) μg/m 3 ) , O 3 (47.1 (4.7-135.4) μg/ m 3 ) and PM 10 particles (25.7 (4.6-146.6) μg/m 3 ) were below the legally defi ned thresholds. Among other results, the occurrence of respiratory diseases showed positive Spearman's correlation with the values of air humidity (days 0-3, r=0.15 to 0.19), PM 10 (days 0-3, r=0.10 to 0.13) and NO 2 concentrations (day 0, r=0.11), and negative correlation with the values of air temperature (days 0-3, r=-0.36 to -0.34), pressure (day 0, r=-0.10) and O 3 concentrations (days 0-3, r=-0.21 to -0.22) (p<0.05 all). In conclusion, the occurrence of respiratory diseases showed correlation with weather conditions and air pollutants despite the legally permitted values in the region with a humid continental climate.