Background: Rheumatic Heart disease (RHD) is by far the most important form of acquired rnheart disease in children and young adults and continues to be a health problem living in manyrnlow and middle-income countries and especially in sub-Saharan Africa. Several strategies havernbeen implemented for rheumatic fever and RHD control. These include primary, primordial andrnsecondary prevention. Benzathine penicillin G (BPG) secondary antibiotic prophylaxis (SAP)rnhas been shown to reduce the risk of ARF recurrences and the development or worsening ofrnRHD with well-established effectiveness. Despite BPG favorable safety profile, a few severernadverse events have been reported and these serious adverse reactions can have a devastatingrneffect on RHD control programs. rnObjective: This study was aimed at assessing the magnitude of the problem of adverse drugrnreaction due to benzantine penicillin and its contributing factor rnMethod: A retrospective cross-sectional study was done among pediatric and adult patients whornare diagnosed to have CRVHD(chronic rheumatic valvular heart disease) and on follow-up atrnpediatric and cardiac clinic respectively and taking monthly benzathine penicillin who came forrnfollow-up from December 2020. to October 2021. The data were entered and analyzed by usingrnSPSS version 25. Data collection was conducted exclusively by the principal investigatorrnthrough telephone interview.Descriptive statistics were employed to summarize the data, andrndata were presented using Tables and Figures. Binary logistic regression analysis was done tornassess predicting factors associated with benzathine penicillin adverse reaction. A p-value