The main purpose of this article was to assess the differences between Seguro Popular (SP) and employer-based health insurance in the use of preventive services, including screening tests for diabetes, cholesterol, hypertension, cervical cancer, and prostate cancer among older adults at more than a decade of health care reform in Mexico. After adjusting for other factors influencing preventive service utilization, SP enrollees were more likely to use screening tests for diabetes, cholesterol, hypertension, and cervical cancer than the uninsured; however, those in employment-based and private insurances had higher odds of using preventive care for most of these services, except Pap smears. Despite all the evidence that suggests that SP has increased access to health insurance for the poor, inequalities in health care access and utilization still exist in Mexico.