Although interest in the social origins of illness has grown recently, the sources of this concern in Marxist thought have received little attention. Friedrich Engels, Rudolf Virchow, and Salvador Allende made important early contributions to this field. Engels analyzed features of the workplace and environment that caused disability and early death for the British working class. Virchow's studies in "social medicine" and infectious diseases called for social change as a solution to medical problems. Allende traced poor health to class oppression, economic underdevelopment, and imperialism. These analysts provided divergent, though complementary, views of social etiology, multifactorial causation, the methodology of dialectic materialism, an activist role for medical scientists and practitioners, social epidemiology, health policy, and strategies of sociomedical change. The social origins of illness remain with us and reveal the scope of reconstruction needed for meaningful solutions.