How do scientific theories come to be accepted? What roles do age, education, type of employment, area of specialization, and familiarity with relevant literature play in the acceptance of theories? The present study was designed to provide preliminary answers to these questions with respect to the theory of plate tectonics and to give direction to a more extensive study of the acceptance of plate tectonic theory. A random sample of 128 Fellows of the Geological Society of America and 87 active members of the American Association of Petroleum Geologists was surveyed in mid-1977. We present the results of that survey and tentative generalizations based on the survey.