High repetition rate solid-state laser systems are used in many scientific and industrial applications. Especially-Q- switched Nd:YAG lasers are gaining increasing importance as pump sources for frequency conversion processes. These lasers are a potential alternative for several classical gas laser systems. Presently, the development of Nd:YAG systems with higher output power and improved beam parameters suffers from limitations imposed by the power handling capability of the optical components. At the Laser Zentrum Hannover, a facility has been installed for the measurement of the multiple-pulse damage thresholds of optical surfaces according to ISO/DIS 11254-2. For an efficient determination of the threshold values, an on-line algorithm calculating the recommended energy for each site has been elaborated and implemented. The most important coating materials for the NIR spectral range were investigated, in respect to their S- on-1 damage threshold. The results indicate the materials dependent reduction of the damage threshold with an increasing number of pulses per site.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.