In the late 19th century, workers' health was among the central concerns of the social reform movement to improve public health. Today, few state health agencies have comprehensive occupational health programs. Yet, state public health agencies have critical roles to play in occupational health and may be particularly instrumental in addressing the occupational health needs of underserved worker populations. Since the mid-1980s, with support from the National Institute for Occupational Safety and Health, the Massachusetts Department of Public Health has been working to build an occupational health program and promote the integration of occupational health concerns with ongoing public health activities in the state. This article provides a framework for considering the range of integration activities and presents examples of successful occupational health integration efforts in Massachusetts.