The aim of the research is finding out the specific features of the regional investment policy and its place in strategic management of agro-industrial complex of Mary El Republic. The article analyses the structure and dynamics of investment processes in the Republic, studies the principles of forming the regional investment policy and the mechanism of the government support of the investors. The conclusion is made on the following: Mary El Republic is one of the regions with well-formed legal regulations in the sphere of investment activity. Its investment policy meets the aims of the long-term strategy of socio-economic development of the Republic and is an effective tool of strategic management of agro-industrial complex. On the grounds of the research done the authors suggest recommendations on increasing investment activity in the agrarian sector: the development of the partnership between state-owned and private-owned businesses, inter-industrial cooperation between the regions of the Russian Federation and other countries and setting up the mortgage investment fund etc.