This paper provides an overview of methodologies used to analyze inter-regional income inequality, and a critical survey of empirical studies that deal with Russian regions. It discusses implications of the growth theory regarding dynamics of inter-economy income inequality. Methodologies for empirically analyzing income inequality are classified as the cross-section approach, distribution approach, and time-series approach. Specific methodologies are described within the framework of this classification, touching upon the subject of their applicability domains. The survey of studies on income inequality among Russian regions summarizes 30 papers grouped according to main approaches used for the analyses.