Long term pollen trend studies are important to precisely estimate the pollen season, and determine the meteorological factor which is effect on pollen concentrations. Ankara is the city which is the longest pollen survey has been done by both of gravimetric and volumetric methods in Turkey. Airborne pollen was monitored by continuous sampling with a Hirst volumetric sampler. We examined the long term trends in airborne pollen concentrations in Ankara, Turkey, over the period 1990-2011 by using linear regression and correlation analysis using mean annual and monthly pollen concentrations. We also tested for general monthly pollen concentration trends and effect of meteorological factors towards between the years. There was decreasing trend in total pollen concentration. We observed a significant increase in January, February, October and November and a decrease in from March to September and December by comparing monthly pollen concentrations. Regarding the pollen-season related attributes, there were very few significant trends. Consequently, pollen could seem to display a faster response to climate change than other airborne particles.