The objective of this study is to evaluate air pollution in Kayseri for the 1990-2007 period. The levels of sulfurdioxide (SO2) and particulate matter (PM) and have been evaluated for the 1990-2007 period by considering the limit values set by Air Quality Protection Regulation (HKKY), European Council (EC) and World Health Organization (WHO). Trends in SO2 and PM values were analyzed for the study period to determine long-term variations in these parameters. The relationships (correlations) between SO2 and PM levels and meteorologic factors were investigated. For the study period average SO2 level was 98 mu g/m(3), while average PM level was 75 mu g/m(3). In winter season air pollution levels were considerably high. Trend analysis showed that SO2 levels decreased with a rate of 6 mu g/m(3)/year (significant at the 0.001 level). Average SO2 levels measured during the heating season and during January, February, September, November, and December were also decreased significantly. In contrast, PM levels did not show any significant trend during the study period. Air temperature values were found to be highly correlated with SO2 ye PM levels. Analyses showed that air quality control strategies (e.g., high quality coal and natural gas usage) put into operation in the past led to the observed decreases in air pollutant levels in Kayseri. However, the SO2 and PM values are still above the limit values set by the EC and WHO.