A multiwavelength Laser Remote Sensing (LJDAR) system (EOLE Project) for daytime and night-time vertical profile measurements of ozone and aerosols in the troposphere and the lower stratosphere (0·5–15 km) is proposed. The EOLE lidar system uses state-of-the-art solid state laser and electronic technologies and is designed to be rugged, modular and simple to operate. Further, in this paper, we present the scientific objectives of the EOLE Project and briefly describe the experimenlal set-up of the EOLE lidar system. The expected measurement accuracy, in both ozone and suspended particles (aerosols) observations, is briefly discussed, as well as the calibration procedures of the proposed lidar system.