The paper describes the feasibility of creating clusters on territories of priority socioeconomic development in mono-profile towns. The authors suggest defining clusters in relation to types of business associations operating in priority development areas within mono-profile towns. The basic principles of the methodical approach were formulated to the formation of clusters in monotowns and diversification of the economy, located on the territories of priority socioeconomic development, based on international and Russian researches made to analyze the experience in the formation and functioning of clusters, their problems and risks. Most significant factors are distinguished for problem solving in mono towns to ensure the sustainable development of clusters. The cluster approach was analyzed with regard to its using in practice. The monotown of Yurga in Kemerovo Oblast (Kuzbass) is described as an example of cluster studies for a discussion of practical considerations in implementing the monotown program designed for priority development areas.