The paper presents a method for estimating the costs of own factors of production on the example of selected holdings keeping their accounts within the framework of the Polish FADN. The starting point for developing the method was provided by the solution applied by the employees of the European Commission. The main assumption underlying these solutions is that the costs of own factors of production are estimated on the basis of the costs incurred by farmers when engaging third-party factors of production (the costs of external factors). The introduction of modifications was preceded by a statistical analysis of factors causing differences in employee remunerations and rents for leased land. The results of the statistical analysis revealed that the cost of unpaid work performed by a farmer's family members should be estimated on the basis of the average remuneration per one AWU in agricultural holdings in a given FADN region and a given economic size class (ES6), the cost of own land - on the basis of the average rent for leased land paid by holdings leasing additional agricultural land in a given FADN region and a given economic class size (ES6), and the cost of a holding's assets - as the value of interests that could be obtained by investing the sum equivalent to the farmer's own capital in long-term security papers. The calculation proposed can also be used for determining two categories of economic surpluses: profit from the agricultural holding and profit of the entrepreneur.