New solutions which would allow for the realization of two basic objectives, i.e. production-related and environmental ones, continue to be sought in plant production. Hence, the purpose of research was to define the impact of five methods of potato field treatment with the application of growth biostimulators and herbicide on the content and harvest of major protein Solanum tuberosum L. Field experiments were carried out in the years 2015-2016 in the region of Eastern Poland (52°02'N; 23°07'E). The experiment was performed in the split-plot system in three replications. The tested factors included: I. Factor – two early edible potato cultivars (Owacja, Bellarosa), II. Factor – methods of treatment with the application of growth biostimulators: GreenOk-Uniwersal Pro and Asahi SL and their combination with Avatar 293 ZC herbicide. As a result of the carried out research, it was noted that the methods of treatment applied in the experiment had a beneficial effect on the value of tested features in comparison to the control object, treated exclusively mechanically (without the use of biostimulators and herbicide). Both in terms of protein concentration and the obtained crop of major protein, the application of mechanical treatment for sprouting of potato plants and Avatar 293 ZC herbicide at a dose of 1.5 dm3∙ha-1 directly before the sprouting and subsequently post sprouting, triple application of GreenOK Universal-PRO bioactivator at the following doses: 0.10 dm3∙ha-1 + 0.15 dm3∙ha-1 + 0.15 dm3∙ha-1 was the most beneficial. The average content of major protein in this object amounted to 8.14% while the average protein yield – 750.09 kg•ha-1.