The objective of this study is to investigate the relationship between immigration status and the patient experience of health care, diabetes self-management, and clinical outcomes among Mexican immigrants with diabetes receiving health care in two immigration sanctuary cities. We used data from the Immigration, Culture and Health Care study, a cross-sectional survey and medical record study of low-income patients with diabetes recruited from public hospitals and community clinics in the San Francisco Bay Area and Chicago. Undocumented Mexican, documented Mexican immigrants, and US-born Mexican-Americans' health care experiences, diabetes self-management, and clinical outcomes were compared using multivariate linear and logistic regressions. We found no significant differences in reports of physician communication, or in measures of diabetes management between undocumented and documented immigrants. All three groups had similar clinical outcomes in glycemic, systolic blood pressure, and lipid control. These results indicate that, at least in some settings, undocumented Mexican immigrants with diabetes can achieve similar clinical outcomes and report similar health care experiences as documented immigrants and US-born Mexican-Americans.