Self-medication in Uganda is becoming alarming and 7 out of every 10 Ugandan students practice self-medication to assess self-medication practices and its associated factors among first-year medical students of KIU₋WC Bushenyi district western Uganda. This was a crosssectional study conducted among 196 registered first-year medical students of KIU-WC who consented to participate anonymously in the study. Data was collected from them with the help of questionnaires which were coded and entered in SPSS version 25 for analysis. Data was then presented in form tables. The majority 90(45.9%) were between the ages of 21 and 24, the majority 72 (36.5%) were Catholics, and the majority 96(56.5%) were males. The prevalence of self-medication was 98.5%. Many 95 (49.2%) got information about self-medication from family and friends, that the majority 86 (44.6%) used strong pain relievers to self-medicate, and that pharmacies/drug stores were the most common source of drugs used in selfmedication, as suggested by 143 (74.1%). The majority of 134 (69.4%) asked someone before self-medicating, with pharmacists being the most frequently questioned 60 (31.1%). Finally, many 99 (51.3%) of those respondents had no idea whether the drugs they purchased could treat their condition. Many 129 (65.8%) self-medicate only for minor medical conditions, the majority 129 (65.8%) say they get better when they self-medicate, many 72 (36.7%) say it is cheap, and the majority 85 (43.4%) say it is convenient. Of the 193 participants who have ever self-medicated, 62 (32.1%) experienced side effects from the drugs they self-medicated with, and the most common side effect was an allergic reaction, as reported by 26/62 (41.9%). The drugs that caused the most side effects were strong pain relievers and antimalarials, as indicated by 20/62 (32.3%) for each category of drugs. The prevalence of self-medication among first-year medical students at KIUWC Bushenyi in western Uganda is high. The common source of information were friends and family,analgesics or painkillers were commonly used drugs and they commonly asked pharmacists before self-medication. The factors associated with self-medication include being 21-24 years, being male, having easy access to drugs or cheap drugs, prior experience with the illness, medical knowledge as well as self-belief in drugs used. Keywords: Self-medication, First-year medical students, Pharmacists, Drugs, pain relievers and antimalarials.