Objective: The purpose of this study was to develop a College Student's Mistrust of Health Care Organizations (CSMHCO) scale and determine the relationship between medical mistrust with the use of a variety of health care services. Methods: A convenience sample of college students (n = 545) at 2 universities in the United States was recruited in the academic year 2010-2011. Results: Using principal components analysis we found that the scale was unidimensional, internal reliability (Cronbach's alpha = 0.85) was good, test-retest reliability was acceptable (r = 0.71), and readability (SMOG = 11 grade) was good. Higher mistrust of health care organizations was found to be statistically significantly associated with all 5 measures of underutilization of health services: failure to take medical advice, failure to seek needed medical care, failure to fill a prescription, postponing needed medical care, and failure to keep a follow-up appointment. This scale seems to be a satisfactory predictor of failure to obtain needed health care services. Conclusions and Translation to Health Education Practice: To help ensure appropriate use of health services by college students this scale could be used to assess levels of mistrust of health care organizations in student populations and then outreach efforts could be implemented for those students most likely to avoid needed health care services. (Contains 3 tables.)