Objective: Polypharmacy, quite common in elderly patients, is an important issue, resulting in increased morbidity and mortality. This study aimed to examine polypharmacy rates and drug usage characteristics in elderly patients. Second aim of this study was to compare our results with other published studies.Methods: In a retrospective design, we reviewed hospital records of 1,205 patients (>=65 years) who presented to our geriatric clinic, which serves as a tertiary center at the University of Istanbul, Cerrahpasa School of Medicine, who were examined in detail in terms of polypharmacy between 2003 and 2012, and who had follow-up care for at least a year. Demographic characteristics, polypharmacy, drugs used at presentation and final evaluation, and comorbid conditions were recorded. The definition of >= 5 drugs usage for polypharmacy and >= 9 drugs usage for excessive polypharmacy were considered in this study. Multivariate binary logistic regression analysis was performed for independent predictive factors.Results: Of patients, 854 were females (70%). The average age was 75.2±6.9. The number of comorbidities was 2.46±1.30. The number of drugs used at first admission and final evaluation was 3.8±2.7 and 4.3±2.8 (p<0.001), polypharmacy rates of 40% and 45% (p<0.001). Also, the rate of excessive polypharmacy was found 8% at final assessments. The rates of patients using one drug, two drugs, three drugs and four drugs were 6%, 11%, 13% and 15%, respectively. Polypharmacy rate in females was statistically significant higher than males (33% vs. 12%; p=0.026). The most common prescribed drugs were found as anti-platelet therapies (70%), calcium channel blockers (68%), anti-osteoporotic drugs (57%), statins (53%), and beta-blockers (49%) in all patients respectively. The most common five comorbidities were hypertension (67%), diabetes mellitus (27%), osteoporosis (27%), hyperlipidemia (25%), and depression (20%). Depression was an independent predictive factor for polypharmacy than other comorbid diseases in the regression analysis (odds ratio (OR): 4.5; 95% confidence interval (CI): 3.2-6.5; p<0.001). Conclusions: The polypharmacy rate was found to be as high as 45% in elderly patients. Before starting an additional medication in elderly patients, particularly with depression, the indication should be clearly specified, and several aspects should be taken into consideration, including functional capacity of the patient, the drugs already used, and possible interactions of the new drug.