This article deals with the problem of assessment of commercial banks financial stability. In the framework of the article are approved methodology for assessing financial stability on the example of regional banks of the Republic of Tatarstan, as well as conclusions about the sustainability of the regional banking system in a worsening debt crisis and the increasing volatility in global financial markets are drawn. Economic and statistical techniques were used: grouping, ranking, a probabilistic assessment, analysis of volume indicators. We have produced results, indicating that there are problems in the activities of the regional banks that undermine stability of the regional banking system and also Russian banking sector as a whole.