The involvement of nonprofit organizations (NPOs) in the delivery of a diversity of social welfare services is an important element of various models of a “welfare mix” approach to the transformation of the modern welfare state. According to the concepts of “third party government” and of “nonprofit organizations” of the welfare state such involvement allows to ease budgetary constraints while enhancing the effectiveness and quality of services delivered. This article is aimed at assessing the outlook for SONPOs in the emerging Russian market for social services funded by the state. The authors primarily analyze the vector of transformation of the regulatory and legal framework providing for the participation of SONPOs in the delivery of state funded social services with the aim to assess how strong the interest of the state to diversify the range of service providers in the social sectors is. The analysis of legal norms is combined with a look at empirical data featuring the attitudes of Russian NPO leaders to cooperation with the state in solving social problems which is an indicator of the likely “responsiveness” of the NPO community to government policy aimed at increasing cross-sectoral cooperation in the delivery of social services. Then the authors proceed with investigating the comparative advantages of NPOs as providers of social services in the light of the concepts of cross-sectoral partnership and welfare mix arrangements in the social sphere. In the article an attempt is then made to test or at least to illustrate in the Russian context the likely validity of the comparative advantages of NOPs as prompted by the mentioned concepts rooted in the “third party government” theory. For this purposes sociological data are used, gathered in the course of a long-term NRU HSE project on Monitoring Russian Civil Society. In conclusion the authors formulate several measures necessary to implement in order that Russian SONPOs can take due advantage of the recent innovative regulation and increase their share as providers of social services funded by the state.