The surface morphology of polystyrene (PS), poly(ethylene oxide) (PEO), (PS) and polystyrene/poly(methyl methacrylate) blend (PS/PMMA) before and after ultraviolet (UV) irradiation was studied by means of atomic force microscopy. It was shown that the UV-induced changes were more noticeable on PS and PS/PMMA blend than on PEO samples. Moreover, the UV irradiation of PS sample doped with poly(methyl methacrylate) caused distinct changes in surface morphology. The nanometer-scale structures of the rod-like shape bumps of diameter of 300 nm and the height of 75 nm were created. We also showed that the very small forces of 0.2 nN are high enough to modify the surface of PS sample.