The results of the X-ray difffaction analysis of ultrahigh-molecular weight polyethylene with montmorillonite crystals have shown the Debye lines to be wide and low-resolved for all the diffraction angles. During the investigation of Fe3+ EPR spectum for montmorillonite single crystals, the effect of crystalline - field multiminimum potential has been revealed in the temperature range from 77 to 300 K It has been also revealed that the position of Fe3+-ion in the electric field is not central. The results of the EPR and X-ray diffraction. analysis done on morillonite and kaolinite nanocrystalls have shown that the spectra are well resolved and can be used in future studies of the texture in nanocomposites of ultrahigh. - molecular weight polyethylene with kaolinite and montimorillonite crystals.