Geosynthetics for all applications have to be tested for resistance to weathering because polymers are generally degraded under the exposure to UV spectral region. EN 12224 and ASTM D4355 describe accelerated weathering tests with different light sources. EN 12224 is based on the 50 MJ/㎡ radiant exposure which is equivalent to one month’s exposure in southern Europe during summer. There are various approaches to reach the same radiant exposure given in EN 12224. The duration is required 320 h for devices with a combination of fluorescent UV lamps, 350 h for devices with UV-A lamps if the lamps are left on during the water spray and 430 h for devices with UV-A lamps if the lamps are turned off during the water spray. ASTM D4355 uses a xenon arc light source having a spectrum that simulates natural daylight, including the UV region. We have performed the accelerated weathering tests according to EN 12224 using combination of fluorescent UV and UV-A lamps, and ASTM D4355 using conventional weatherometers. In this study, we have investigated the effects of different light sources on degradation properties of non-woven geotextiles.