Questions of management of a public debt became one of the central in economic and political life of territorial subjects of the Russian Federation in recent years. The special importance is gained by an assessment of efficiency of expenses on service of a public debt. The study reveals the factors influencing the cost of finan-cial loans of territorial subjects of the Russian Federation, and gives the formulas to calculate inefficient volume of a public debt, inefficient expenses regarding attraction of the budgetary credits, inefficient expenses on short-term loans, volume of inefficient expenses on payments on repayment and service of a public debt.