Diarrhea is among the top ten killers worldwide and in 2015, it accounted for 11% of child deaths globally. Many of these cases are from low and middle-income countries including Uganda. The last Uganda Demographic and Health Survey (UDHS) report in 2015 showed that the prevalence of childhood diarrhea was 19.5%. The local prevalence in Hoima was not known as no study had been done concerning the subject. The purpose of this study therefore was to identify the prevalence of diarrhea and its associated risk factors among children aged under five years presenting at Hoima Regional Referral Hospital. A cross-sectional descriptive study design was adopted for this study. Data was collected from 241 mother-child pairs using a pretested semi structured questionnaire. Collected data was entered in the computer after cleaning and analyzed using IBM SPSS version 25. Descriptive statistics were one to get the prevalence of diarrhea while Chi square and binary logistic regression analysis was done to find the independent variables associated with diarrhea among children under 5 years. The prevalence of diarrhea among under 5 years old in this study was 12.4%. The risk of diarrhea was increased in non-working mothers (OR=8.571; CI=2.889-25.426; p<0.001), child’s age between 6 and 24 months (OR=9.098; CI= 3.282-25.220; p<0.001) and unprotected water sources (OR=12.100; CI=3.559-41.133; p<0.001). Christian religion (OR=0.263; CI=0.090- 0.768; p=0.015), and not using bottle feeding (OR=0.229; CI=0.104-0.507; p<0.001) showed a reduced risk of diarrhea. The present study showed a high prevalence of diarrhea among children under five years of age. The independent variables that were found to be associated with diarrhea were mother’s working status, child’s age, source of drinking water, religion and bottle feeding. The results of this study have serious policy implications for health intervention programs and the researcher recommends that promoting women income generating programs may have a significant importance on child health and survival in the study area and Uganda in general. The longterm solution for decreasing morbidity from diarrhea may include the delivery of improved sanitation and hygiene through efficient health educational programs that concentrate on personal hygiene which lead to full sanitation. This should be reinforced in combination with health workers educating households on sanitation and child feeding practices. Keywords: Diarrhea, Children under 5 years, Mothers, Women, Child deaths.