The article deals with the problem of diagnostics of the enterprise carried out before its acquisition. With the implementation of the integration, strategy investors need to have accurate information about financial and economic activity of the company is the investment object. For complete information to legal, tax, financial expertise and valuation expertise that would make an informed management decision. When conducting tax examiner identifies problems in the tax sphere on the calculation, payment of taxes and estimated risk of litigation. Legal expertise is necessary for conformity assessment of financial and economic activity of the company is the investment object to the legislation. Valuation expertise allows you to determine the market value of the whole property complex, as well as to evaluate the existence of encumbrances of property. The ongoing financial expertise uses information in other types of examinations, and shall confirm or reveal discrepancies between actual performance and stated. The algorithm of diagnosing enterprise-investment object can be applied to all enterprises regardless of the organizational-legal form, industry ownership.