Purpose: Diabetes imposes a significant economic burden on employers, particularly when including productivity costs. Given the great interest on multicomponent lifestyle interventions in these individuals, we assessed the short-term and long-term efficacy of a structured lifestyle modification program, My Unlimited Potential, among employees with diabetes of Baptist Health South Florida (BHSF), a large non-for profit health-care system. Design: This is a pre- and post-effectiveness of a workplace health promotion program. Setting: Worksite intervention at BHSF. Participants: The study analyzed the data of 93 employees with diabetes involved in a worksite wellness program after completion of a year long program. Intervention: The intervention was an intense lifestyle modification program that was targeted to the individual needs of the participants. Measures: Cardimetabolic risk factors such as body mass index (BMI), weight, systolic blood pressure, diastolic blood pressure, glycated hemoglobin, total cholesterol, triglycerides, high-sensitivity C-reactive protein, low-density lipoprotein, high-density lipoprotein, and maximal oxygen consumption. Analysis: Paired 2-sample t tests for means and descriptive statistics were used. Results: A mean decrease of 0.6 percentage points was observed in HbA1c values from baseline to 12 months. Weight, BMI, blood pressure, and lipid profile improved significantly after 12 months. Conclusion: This study suggests worksites with existing health promotion programs, and health-care staff can effectively deliver a diabetes prevention program that appears to have a long-term impact on employee health.