Polyisoprene/nanostructured carbon (PNC) composites are known for their ability to change electrical resistance rapidly under the influence of mechanical strain and vapour of volatile organic compounds. Previously testing of PNC composites containing carbon black (CB) filler were made to check for the possibility to sense optical radiation. In this study attempt to determine the difference in resistance change response depending on laser wavelength was done. PNC composite samples cyclically were irradiated with laser beams of different wavelengths. Irradiation time during one cycle was 30 s. Measure-ments with sample containing 8 phr of CB showed that relative resistance change effect is larger when irradiating the sample with 532 nm laser beam compared to 980 nm laser beam. To clarify the mechanism for such difference in relative resistance change further PNC composite tests are being made.