This paper deals with the debate which opposed Sismondi and the Ricardian economists, in the first half of the nineteenth century, on the equilibrium of markets, the role of competition and the effects of machinery in industrial societies. At the initial section, the main content of Sismondi?s critical rhetoric toward the classical orthodoxy is reconstituted. After that, the replies of McCulloch and Colonel Torrens are detailed, specially their defense of free competition and the unlimited character of demand, as well as of the inroads of machinery in the productive process. The third part considers Sismondi?s rejoinder when he reinforces his theory of a general glut from a historical perspective of capitalism. In the end, and having in sight this particular controversy, a brief assessment of Ricardo?s legacy to political economy is made.