The discussion on sustainability of development is followed by constant search for its appropriate indicators. If the authors dealing with sustainability in agriculture manage to cover all three its dimensions (economic, environmental, and social), they quite often calculate joint indicator as a simple sum or (sometimes weighted) average of three partial indicators, not paying enough attention to the balance and interdependencies between the partial indicators. The goal of this paper is to measure and assess the interdependencies between partial sustainability indicators. Basing on literature and expert knowledge, the authors prepared 109 questions in order to construct 7 partial indicators of sustainability: correctness of farm management practice (crops), correctness of farm management practice (animals), understanding environmental issues, production potential, economic potential, living conditions of the farmer's family, farmer's psychological comfort. The research was carried out in 600 farms that participate in Polish FADN, based on standard FADN data and additional information based on interviews with farmers. The analysis revealed that the partial correlations between partial indicators was relatively strong and negative, which means that reaching all sustainability goals simultaneously is a difficult issue, as they compete with each other. It is concluded that assessing farm sustainability with the use of simple aggregation of variables is not correct.