In preparing theoretical tools to analyze economic systems we need several fundamental concepts that are often applied in various scientific investigations outside economic studies. Amongst others, the concept of autopoiesis, which was introduced by Niklas Luhmann into his sociological systems theory, is the most important in constructing a theoretical model to explain the working of economic systems. An autopoietic system may be regarded as the functional core by which other elementary concepts such as homeostasis, machinery, corporate system and social entropy can be logically connected. In conclusion, all economic systems are contained in distinct social systems of autopoietic character and incorporated with them as a subsystem or partially independent system.