The paper presents some Polish experiences in the field of decision support systems (DSS), especially the one concerning the selection of farm equipment and choice of the system of its use. A decision support system elaborated at the Institute for Building, Mechanization and Electrification in Agriculture (IBMER) is based on mathematical models describing correlations between working conditions, technological parameters, prices of machines and the operating cost of farm machinery. The system facilitates choices concerning the size of tractors and machines Jbr family farms and the method of use (private, multi-farm or contractor) under present Polish conditions. The system is intended for agricultural advisory services. The system can be used by those with access to a microcomputer IBM PC. In Poland these are agricultural extension centres providing advisory services to private farms.