The black lung movement that erupted in West Virginia in 1968 was not simply a struggle for recognition of an occupational disease; it grew into a bitter controversy over who would control the definition of that disease. This article examines the historical background and medical politics of that controversy, arguing that black lung was socially produced and defined on several different levels. As a medical construct, the changing definitions of this disease can be traced to major shifts in the political economy of the coal industry. As an occupational disease, the history of black lung is internally related to the history of the workplace in which it is produced. As the object of a mass movement, black lung acquired a political definition that grew out of the collective experience of miners and their families. The definition of disease with which black lung activists challenged the medical establishment has historical roots and justification; their experience suggests that other health advocates may need to redefine the diseases they hope to eradicate.