Abstract: The clay mineralogy of paddy soils with different water table depth and drainage of Northern Iran were investigated to determine their origin and factors controlling their distribution pattern in soils. In this study sand, silt and clay fractions were separated by centrifuge after the removal of organic matter, carbonates and sesquioxides. For identification of clay minerals, clay suspensions were saturated by Mg and K and then 10 mg of clays were placed on glass slides for XRD analysis. In all of the soils studied, smectite, illite, chlorite, kaolinite and quartz were identified. Clay mineralogy is probably more affected by parent materials and less influenced by aquic and anthraquic conditions. However, there are some indications that aquic and anthraquic condition may affect on quantity of clay minerals, as shown by higher smectite in poorly drained soils.