The diploma thesis deals with the survey of the condition of wooden elements nine of selected observation towers - Na háji, Radošinka, Na Dubni, on the Špicák hill, Maginhrad, Slopovo, on the Prašný hill, Opava, Skalka near Počúvadlo and one sightseeing tower Vršatec. Towers were built between 2002 and 2018. The in-situ survey was carried out in March and April 2019., The supporting pillars of the observation tower on the Prašný hill and Skalka near Počúvadlo were made from oak wood, Opava, Slopovo, Radošinka and sightseeing tower Vršatec were made from larch wood. Observation tower on Špicák hill and Maginhrad were made from spruce wood. Glued laminated timber were used on observation tower Na háji. Na Dubni lookout tower has a steel bearing structure. The visual survey of the current state of wood elements was focused on the occurrence and extent of disorders caused by biological and abiotic agents. The survey also included the classification of the structure and its wood elements into the hazard classes according to EN 335. In the case of the Opava and Skalka observation towers, the visual survey was supplemented by a closer identification of the extent of rot found on the supporting elements by means of nondestructive ultrasonic measurements using the Fakopp Ultrasonic Timer. The current state of wooden elements is suitable in the following observation towers: Na háji, Radošinka, Na Dubni, Špicák hill, Maginhrad, Slopovo and Vršatec lookout tower. Due to fact that wooden elements of observation tower on the Prašný hill have not been surface-coated it has been found to exhibit surface weathering aging of wood there, namely, the gray tint and the initial stages of weathering on the front surfaces of wooden elements. Significant damage to supporting wooden elements by brown rot was found in two observation towers - Opava and Skalka near Počúvadlo