Existing standards and methods of business planning are universal in nature, regardless of whether they are used for a newly created business or for the implementation of projects in existing production. The lack of well-developed methodological recommendations that take into account the specifics of the formation and implementation of business plans for existing production determined the choice of the topic of the dissertation. The purpose of the thesis: improving the methodological approach to the development of business plans in existing production. Research Objectives: study of the theoretical and methodological foundations of business planning, analysis of foreign and Russian experience in business planning in the framework of existing production; development of a methodological approach to business planning at the existing production, testing of the developed methodological approach at the LLC «Ekomash + Ural» enterprise, assessment of its economic efficiency. A methodological approach to business planning at the existing production is proposed, including an updated scheme for the implementation of the stages of developing a business plan with identification of the specifics of each stage for the existing production and methodological recommendations for the implementation of individual stages, which allows to increase the efficiency of projects and production and business activities carried out at the enterprise whole. Using this technique at the LLC «Ekomash + Ural» enterprise allowed increasing the load factor of equipment, reducing the cost of purchasing materials and raw materials, as well as wages for employees.