The subject of the author's considerations is the "pig cycle" phenomenon, which had been first formulated by Samuel Benner in 1895. Since then, the mechanism of the pig cycle has been investigated and discussed by many foreign and Polish scientists. The key fields of American studies on the pig cycle such as: reasons for cyclic development of pig production, cobweb theorem, duration of the cycle and its particular phases, are presented in the article. The results of researches conducted during the last several years are also discussed. An important part of the article is devoted to the Polish pig cycle in both pre- and post-World War II periods. In the post-war period the researchers who examined the pig cycle problem had to face a difficult question whether cyclic fluctuations of hog production could take place in centrally planned economy. The article also points out a very practical aspect of the study, related to stabilization of the pig market. Different approaches to agricultural policies in some countries and periods are also presented.