Patient activation refers to people's ability to engage in self-management of their health and health care. We assessed the performance of the Patient Activation Measure (PAM) for patients attending three inner-city health centers and compared resultant scores with those of the general U.S. adult population. We approached 801 patients and 527 (65.8%) participated; the majority were Latino(a) or African American/Black. No differences in activation were seen according to age. Males and more educated patients were more activated (p<.05) and patients with better self-rated health and adequate health literacy were more activated than their counterparts (p<.001). Patterns of scores resembled those of the U.S. general population for educational attainment and self-rated health but not for gender and age. Compared with the general population, more patients were characterized as level 1 (least activated). Developing strategies that enhance patient activation is critical to improving health outcomes, particularly in less advantaged populations.