The morphology of films of PDS/PP blends with various content of PDS and with PDS of different molecular weight was examined by scanning electron microscopy and the photostability of these films was studied by infrared spectrometry. Experimental results show that PDS is dispersed in PP matrix as spherical globules being in size of the order of 10-1 μ when content of PDS is in the range of 0.1% to 1%. The phase separation of PDS from PP results in decrease in photostabilizing action of PDS to some extent. It is found that films of PP biended with PDS of different molecular weight show similar morphology and photostabilizing action if the content of PDS is kept the same.