The study was aimed to investigate the effects of air pollutants particulate matter (PM 2.5, PM 10 ), sulfur dioxide (SO 2 ) and NO 2 on hospital admissions for respiratory diseases in the residents of Nis, Serbia, during the period 2012-2014. The findings of average daily concentrations of air pollutants were obtained both by the measurements made by the Public Health Institute Nis and by the state ambient air quality monitoring network of the Agency for Environmental Protection of the Republic of Serbia. The respiratory diseases analyzed in the study are pneumonia, asthma, and chronic obstructive pulmonary disease (COPD). Patients were categorized into three age groups (0-17.9, 18-64.9 and >65). Poisson regression was used to examine the link between air pollutants and respiratory health outcome at lag 0. Results was expressed as the increase in Relative Risk (RR) for hospital admissions for each daily increase in air pollutants for 10 µg/m 3 . NO 2 had the most significant effect on hospital admission, although its concentrations did not exceed the prescribed values. With an increase in the daily NO 2 concentrations of 10µg/m 3 , the RR of daily asthma and COPD hospital admissions in Nis older than 65 years increased by 1.2% and 0.7%, respectively. In women older than 65 years, with an increase in daily concentrations of NO 2 of 10µg/m 3 , the risk of daily hospital admissions for asthma increased by 1.5%. In multi-polluted statistical analysis (adjusted with PM 2.5 and SO 2 ) each daily increase in NO 2 for 10 µg/m 3 was statistically significant associated with the increased RR by 1.3%. In men 18 to 64 years of age, with an increase in daily NO 2 concentrations of 10 µg/m 3 , the RR of hospital admissions for asthma increased by 2.0%, and in the PM 2.5 -adjusted model, increased by 1.8%. The suspended particles had an effect on hospital admission for pneumonia in men up to 17.9 years of age. With an increase in daily concentrations of suspended PM 2,5 particles of 10 µg/m 3 , the risk of hospital admissions for pneumonia in them increases by 0.6% and 0.4%, respectively. We found that the concentration of NO 2