Comorbidity rates in the geriatric population have increased because of rising life expectancy; thus, patients have had to use more medications. Type 2 diabetes mellitus, one of the most common diseases, may influence the number of drugs used in geriatric patients. The present study was designed to investigate the association between the level of type 2 DM and polypharmacy. Fifty patients with type 2 diabetes over the age of 65 were included according to the inclusion criteria; 23 were well-controlled and 27 had poorly controlled diabetes. The groups were similar in terms of age, sex, WBC, Hb, Plt, AST, ALT, serum creatinine, fasting glucose, and eGFR levels. Patients with HbA1c values above 7.5 were classified as poorly controlled diabetes patients, and those below were considered well-controlled diabetes patients and were evaluated for inappropriate medication use. The number of medications used daily by the cases (p < 0.001), the number of concomitant diseases (p = 0.001), and the number of increased risks according to the Beers Criteria (p = 0.02) were observed to be high in poorly controlled type 2 diabetes mellitus subjects. HbA1c levels were related to the number of medications (r = 0.4, p = 0.004), comorbidities (r = 0.28, p = 0.04), and the number of increased risks according to the Beers Criteria (r = 0.31, p = 0.014). In conclusion, the number of medications used in patients with poorly controlled type 2 diabetes mellitus was found to be more elevated than in individuals with well-controlled type 2 diabetes mellitus. The HbA1c values varied among patients regarding polypharmacy, comorbidities, and increased risks according to the Beers Criteria.