9 TL samples of the loess profile Rheindahlen (Lower Rhine Area, Germany), covering the time span of the last 300 ka, were studied. Systematic investigation was carried out using different filters and preheating procedures. ED determinations were done by the additive dose and the regeneration method. The annual dose was determined by AAS, alpha counting, NAA and gamma spectrometry in the laboratory and in the field. The results show that the Weichselian loess is datable whereas no TL age differentiation between loesses of Stage 6 and Stage 8 is possible. If the accumulated dose (ED) is in the ‘600 Gy region’, every apparent TL age between 100 and 300 ka can be obtained. This leads to the conclusion that in Rheindahlen no reliable TL ages are available for loess deposits underneath the Eemian soil (Stage 5e).