On the territory of Oltenia (region located in the SW part of the Romanian Plain) are encountered on large surfaces red loess or loess like deposits of Quaternary Age. This kind of deposit is described in the literature as “red clay” or “red loams”. Similar deposits of different ages can be found in Northern Bulgaria or Hungary. This article presents data on the type and proportion of clay fraction (<2μ) minerals identified using X-ray diffraction and IR absorption analysis. The clay fraction was separated from both the loess like deposits and older deposits below them. All older deposits of gravel-sand matrix are coloured red due to iron oxides. The sample collection area location is the village of Valea Anilor in Mehedinţi County, about 30 km east-northeast from the Danube, Porțile de Fier. Two different methods were used to separate the clay fraction, both being presented for clear understanding of the analytical conditions. The identified clay minerals are of three types: illite, smectite and kaolinite. The most abundant kind of clay mineral it is illite, representing over 50% of clay sized fraction and the least present it is kaolinite with a presence of maximum 5%.