Quantitative models have been widely used in cosmology, physics and chemistry for a long time. The use of these models has led to a thorough knowledge of the reality under study. During the last decades important growth has been recorded in the number of quantitative models in the social sciences, and particularly in economy. These researches are expected to allow a better description and control of economic phenomena, which are more complex than physical ones. At first, cybernetic systems are defined, then the possibility of studying certain types of equations with analogical methods is analyzed, and in the end several cybernetic models for economic growth are presented.