There are presented analysis of machinery operating costs in 143 family farms between 5 to 30 ha. Average costs is 5,7 thousand zl per farm. The main part of costs consist fuel and oil - about 43%, investment - 24%, maintenance and repair - 23% and insurance. The analysis shows that factor used for calculations, like repair factor or period of ownership, are often overestimated which results higher costs comparing with real financial inputs.