The Lago Bianco dam is a concrete gravity wall, which was built in 1911. The height of the dam was increased from 12 m to 16 m in 1942. Several conventional sensors accurately monitor the dam, including extensometers, piezometers, thermocouples, joint meters, GPS and geodetic instruments. Although the already existing sensors are adequate for monitoring the dam, an additional distributed fiber optics monitoring sensor system (DFOS) has been installed: The main goal was to verify the measurements of the conventional sensors, in particular strain, temperature and concrete crack development but with significantly higher spatial resolution. The DFOS were installed in a two dimensional grid on the downstream side of the dam and it was interrogated for more than four months on different time intervals. The DFOS enabled accurate and precise distributed measurements of the variation of temperature and strain of the dam surface. The collected data are in good agreement with the local measurements of the conventional sensors. Additionally, the DFOS allow for a more comprehensive understanding of the dam mechanical behaviour