Given the diversity of human uses and natural resources that converge in coastal waters, the potential independent and cumulative impacts of those uses on marine ecosystems are important to consider during ocean planning. This study was designed to support the development and implementation of the 2009 Massachusetts Ocean Management Plan. Its goal was to estimate and visualize the cumulative impacts of human activities on coastal and marine ecosystems in the state and federal waters off of Massachusetts.For this study, regional ecosystem experts were surveyed to gauge the relative vulnerability of marine ecosystems to current and emerging anthropogenic stressors. Survey results were then combined with spatial information on the distribution of marine ecosystems and human stressors to map cumulative impacts in Massachusetts waters.The study resulted in an ecosystem vulnerability matrix and human impacts maps, which together yield insights into which ecosystems and places are most vulnerable and which human uses, alone and in combination, are putting the most stress on marine ecosystems. These products can be used in a number of ways, including to help clarify ocean planning decisions, identify areas of potential conflict among ocean users and areas that may merit conservation, and assess ecological, economic and social values of particular places.