Systematic lidar measurements of aerosol backscatter and extinction in the troposphere were performed since May 2000 with the aerosol lidar system operational at IMAA-CNR in Tito Scalo (Potenza) (Southern Italy, 40°36’N, 15°44’E, 820 m above sea level) in the framework of EARLINET. EARLINET is the first European network of 22 advanced lidar stations operating to provide a quantitative climatological database of the horizontal, vertical and temporal distribution of aerosols over Europe. Aerosol backscatter measurements were performed at both 355 nm and 532 nm, while aerosol extinction coefficient was retrieved from simultaneous N2 Raman backscatter signals at 386.6 nm. The lidar measurements at IMAA have been performed according to a regular schedule of two night time measurements per week (around sunset) and one daytime measurement per week (around 13:00 UT). Further measurements were devoted to observe special events such as Saharan dust, forest fires and volcanic eruptions. A statistical analysis on climatological aerosol extinction-to-backscatter ratio (lidar ratio) data, covering more than three years of systematic lidar observations, has been carried out. These lidar ratio data, in conjunction with an analysis on the air masses backtrajectories, provide information on microphysical properties of the aerosol on a wide range of meteorological conditions. Results obtained starting from both climatological data and special events (Saharan dust and volcanic eruptions) are presented and discussed.