Wood is susceptible to photo-degradation in outdoor applications, and deformations occur on its surface such as micro or macro cracks, color changes etc. Especially, cracks make wood material more vulnerable to biotic attacks. In this study, decay resistance of natural and accelerated weathered beech samples was investigated by a brown (Coniophora puteana) and white rot (Coriolus versicolor) fungi attacks. For this purpose, beech samples exposed to natural weathering (NW) for 393 days, and accelerated weathering (AW) for 1512h, and then subjected to decay test in malt extract agar medium for 2 and 4 weeks. After 2 weeks of decay testing, weight loss of samples by C. versicolor was found to be 24.30% for controls, 13.29% for AW samples and 24.38% for NW samples. In the case of C. puteana, it was found as 21.15%, 21.49% and 30.61% for controls, AW samples and NW samples, respectively. Weight loss of samples by C. versicolor was found to be 61.82% for controls, 30.72% for AW samples and 37.62% for NW samples, after 4 weeks of decay testing. The weight loss by 4 weeks exposure of C. puteana was found to be 21.43%, 28.44% and 37.67% for controls, AW samples and NW samples, respectively. Natural weathering caused more weight loss than accelerated weathering test for both fungi species.