Laser light as a pure ecological factor started to be used as a plant biostimulator. It is especially important in the case of short exposures to laser light. However, prolongation of irradiation induces damage to genetic material in plant cells. Hence, laser can be treated as inducing mutation. As compared to ionizing radiation or chemomutagens, laser shows a markedly lower mutagenic ability and contrary to other mutagenic agents, induces low degree of biological injuries in the M1 progeny. Specific properties of laser that provids light in red at a well-defined wavelength (630-650 nm), and strong mutagenic characteristics of chemomutagen N-methyl-N-nitrosourea (MNU) made us apply both of them in the combined treatment for biostimulation and mutation induction. The seeds of the original material (three brewery barley cultivars) were irradiated with different doses of helium-neon laser light and MNU. The following combined treatment: laser + MNU and MNU + laser was used without application of a single treatment with laser or MNU. In the M1 progeny, the biostimulative effect and degree of reduction were estimated. The influence of laser and MNU on the mutation frequency was analysed in the M2 and calculated as a percentage of chlorophyll mutants in the total M2 population. Analysis of the M1 plants showed that, irrespective of the kind of initial material, short exposure to laser (30 min) induced biostimulation effect on the yield parameters. Higher doses of laser (120 min) as well as MNU induced only reduction of the analysed traits. Among the analysed material, cultivar Boss showed higher susceptibility to the applied doses of MNU and laser than cv. Rambo and Rudzik. In the M2 progeny, the combined treatment induced higher mutation frequency than an individual treatment with laser or MNU. It was particularly true for cv. Boss and combination of MNU with 120 min of laser light. The results obtained indicated advantages of laser application in the combined treatment with MNU, as compared to a single treatment.