The article investigates the peculiarities of the simplified taxation system in Ukraine and the main changes that were caused by the beginning of the war. It was determined that such a system has several shortcomings that affect the single tax's fiscal, regulatory and incentive efficiency. Nevertheless, the simplified taxation system plays a crucial role in the development of the direct entrepreneurial activity, which directly impacts the level of technological, investment and economic development of the country, as entrepreneurs are the driving force behind the development of IT, trade and services. Based on the analysis of tax changes in the direction of the simplified taxation system and experts' opinions on their appropriateness and vice versa, we believe that such a system is necessary for the functioning of the current small and medium-sized businesses. In the case of increasing tax rates or changing tax objects, it can contribute to the shadowing of business. Especially the issue of abandonment of the simplified taxation system cannot be raised in the current military conditions when one of the important items of budget formation is the voluntary payment of the single tax by entrepreneurs. That is, the practical analysis of the application of permitted tax mechanisms to minimize tax payments during the war made it possible to summarize the simplified taxation system's shortcomings and propose appropriate recommendations that will increase the fiscal and stimulating effect of the single tax. The identified recommendations will ensure the filling of the budget by introducing a progressive single tax rate, providing for a separate taxation group for IT specialists, controlling the legality of the use of benefits provided for the period of war, etc. At the same time, the stimulating function of the single tax is possible due to free consultations (the need for which was proved by the Google Trends tool), the launch of social media, and the increase of additional opportunities for expanding activities for all areas of economic activity. We believe that the implementation of the proposed recommendations will stimulate the further development of small and medium-sized businesses.