Purpose Diabetes impacts a significant population in the United States, with uncontrolled diabetes leading to serious adverse health effects and substantial cost to the healthcare system. Diabetes management by clinical pharmacy services (CPS) demonstrating positive clinical outcomes has been well-established in the primary care setting. However, there is little data evaluating the impact of CPS in specialty clinics such as endocrinology, which may provide additional opportunities for pharmacists to improve outcomes in a complex patient population. The purpose of this study is to describe the implementation of CPS in an ambulatory endocrinology clinic and to evaluate the impact of pharmacist care on diabetes management. Methods This was a retrospective, pre- post- descriptive study. Patients were enrolled into the study during a 6-month period and followed for a minimum of 6 months. The primary endpoint was mean change in hemoglobin A1c (HbA1c) between the pre- and post- pharmacist intervention phase. Secondary endpoints included blood pressure outcomes, statin appropriateness, rates of hospital and Emergency Department (ED) admissions due to severe hyper- or hypo- glycemia, and rates of retinal screening exams. Results A total of 101 patients were included in the study population. The mean baseline HbA1c was 9.11% and at six months 8.27%, with mean change of 0.84% (p-value <0.01). Descriptive statistics showed that blood pressure control, as well as statin and retinal screening rates, were high at baseline, with CPS making limited interventions in these areas. Conclusion This study demonstrated that pharmacist interventions in diabetes care is associated with improved HbA1c for a complex patient population in an endocrinology clinic.