The present study takes a culture-centered approach to better understand how the experiences of culture affect patient's perception of type 2 diabetes mellitus (T2DM). This study explores personal models of T2DM and compares personal models across regional and race/ethnicity differences. In a practice-based research network, a cross-sectional survey was distributed to patients diagnosed with T2DM at medical centers in Nevada and Georgia. In analyses of covariance, controlling for age, health literacy, and patient activation, geographic location, and race/ethnicity were tested onto 5 dimensions of illness representation. Among 685 patients, race/ethnicity was significantly associated with lower reported understanding diabetes ( P < .01) and less perceived longevity of diabetes ( P < .001). Geographic location was significantly associated with seriousness of the disease ( P < .005) and impact of diabetes ( P < .001). Non-Hispanic White Americans report greater understanding and perceive a longer disease course than non-Hispanic Black Americans and Asian Americans. Regionally, patients in Nevada perceive T2DM as more serious and having more impact on their lives than patients living in Georgia. Primary care physicians should elicit patient perceptions of diabetes within the context of the patient's ethnic and geographic culture group to improve discussions about diabetes self-management. Specifically, primary care physicians should address the seriousness of a diabetes diagnosis and the chronic nature of the disease with patients who belong to communities with a higher prevalence of the disease.