Background: Polypharmacy is one of the major concerns in the healthcare sector as it has arnstrong association with increased treatment costs, morbidity and adverse drug reactions (ADR).rnElderly patients are prone to these risks for they are exposed to many coexisted chronic and acuternillnesses that lead to polypharmacy. In Ethiopia, there is a dearth of studies exploring thernprevalence and associated factors of polypharmacy in elderly patients. rnObjective: To determine the prevalence of polypharmacy and its associated factors amongrnelderly patients admitted to Federal Police Referral Hospital (FPRH) in Addis Ababa, Ethiopia. rnMethods: A healthcare facility-based, retrospective cross-sectional study was carried out inrnFPHR, one of the two federal-level military hospitals in Addis Ababa. Medical charts of elderlyrnpatients who were admitted to the hospital in the period 01 January 2019 to 01 January 2020rnwere reviewed for polypharmacy. Using an adapted and structured data extraction tool, data werernabstracted on patient characteristics, diseases encountered, co-morbidities, and the type andrncategories of the drugs administered. Data were analyzed using SPSS software version 25.rnLogistic regression was used to assess the association and an odds ratio (OR) with arncorresponding 95% confidence interval (CI) was used. rnResults: A total of 376 medical charts were reviewed, of which five or more drugs werernprescribed in 180 (47.9%) charts, with a mean of 4.57. This indicated the occurrence ofrnpolypharmacy in FPRH. In the logistic regression, cardiovascular disease (AOR = 7.456, 95% CIrn[2.109 - 26.360], p = 0.002) and endocrine disorders (AOR = 7.331, 95% CI [1.988 - 27.043], p rn= 0.003) showed a significant association with polypharmacy. rnConclusions: Polypharmacy is highly prevalent among elderly patientss admitted to FPRH.rnCardiovascular disease, endocrine disorders, and comorbidity with one to three diseases were thernmajor predictors of polypharmacy. We recommend that medication practices for elderly patientsrnneed to be improved through training of clinical practitioners, regular review of patientsâ€™rnmedication charts, particularly patients with cardiovascular disease and endocrine disorders, andrnfurther ingagement of clinical pharmacists in elderly care and treatment.