Gypsiferous lands comprises an important land resources of arid and semiarid regions of the world. Based on the recent estimations they are also widespread and very extensive in arid parts of Iran . Differnt behavior of gypsiferous soils comparing with other soils dominated by sillicate clay minerals ,and difficulty in evaluating some important physicochemical properties from the analitical results obtained by application of standard methods is a controversial subject in this kind of soils.In the present study after classification of some of these soils at south west Gilanegharb (Kermanshah) their phisicochemical properties have been studied and the results of some analytical methods have also been compared . The soils have been classified as Aridic Ustochrepts and Calcic Ustochrepts . The amount of gypsum measured with different methods showed a wide range between 0-97 % . The soil texture after elimination of gypsum was always finner comparing with the samples before removing gypsum and they were usually clay loam to silty clay loam whereas in samples with gypsum they showed mostly loamy texture . The CEC showed a negative correlation with the gypsum percentage and it ranged between 5-18 cmol(+)/kg .The dominant cation is allways calcium and due to little amount of K+ and Mg2+ in the soil solution the low ratio of K/Ca and Mg/Ca is also an important characteristcs of these kind of soils .Sulfate is also the most dominant anion. The soil pH is on the range of weak alkaline and the amount of salts more soluble than gypsum is usually very low and the EC of saturated soil extracts is mainly below 3 dSm1
)