OBJECTIVES: Identification of the diseases and disabilities that encumber the economy the most, is extremely important. An accurate analysis of the economic burden by specific diseases and disabilities and their interrelationships, particularly in the publicly financed areas, can significantly support the improvement of the allocative efficiency of resources in health. This study is the first comprehensive study on the direct and indirect costs of all diseases and for some selected disorders their related complications, in Poland. Complications of the following diseases have been analysed: depressive episode and recurrent depressive. METHODS: In order to estimate the direct medical costs of disorders and for some selected disorders the costs of their complications, data from the National Health Fund were used with related etiological fraction calculus. This data includes the costs of outpatient consultation, hospitalization, rehabilitation, and drugs. Indirect costs embraced costs of lost productivity due to absenteeism and inability to work (handicap) caused by these diseaeses, and costs of lost productivity due to the premature mortality. They were calculated upon Social Insurance Institution and Central Statistic Office datasets using human capital method. RESULTS: The total cost of diseases in Poland (including lost productivity of persons insured in Agricultural Social Insurance Fund) amount to EUR 37,9 billion, of which 61% (EUR 23.0 billion) is the cost of lost productivity (indirect), and 39% (EUR 14.9 billion) is the cost of health-care services (direct). Analysis of costs of selected mental disorders and their complicatios indicates that costs of disease-related complications are much higher than disease itself (total costs of mental disorders – EUR 372,2 million, total costs of mental-related complications – EUR 1,127 billion). CONCLUSIONS: The conducted analysis indicates that diseases constitute a significant burden for the Polish economy. Total cost of diseases constitutes 9.5% of the GDP in Poland (the indirect cost is 6.06% of GDP).