Cost calculations applied in dairies do not separate subsidiary production. Costs of production and operation of electric power, water, steam, refrigeration, compressed air and waste treatment were calculated for one dairy on the basis of own calculation method presented in earlier papers. Analysis of structure of the costs in question, as well as of their dependence on production varying in successive months, was made. Certain irregularities in the shape of unit cost lines were found in some months. Reasons for their appearance may he explained in the course of further investigation concerning energy management in a dairy, taking into account all places of cost arising.