Two optical disdrometers, OTT Parsivel² disdrometer and Thies Clima laser precipitation monitor (LPM), are compared. Analysis of 2 years of one-minute replicated data showed significant differences. Thies LPM recorded a larger number of particles than Parsivel² and a higher proportion of small particles, resulting in higher rain rates and amounts and differences in radar reflectivity and kinetic energy. Possible causes for these differences, and their practical consequences, are discussed.