Pneumonia, a respiratory infection that affects the lungs, causes inflammation of the alveoli due to various pathogens. It poses a major public health risk, especially in children under five, contributing significantly to mortality rates in low- and middle-income countries like Ethiopia. This study aimed to assess the prevalence of pneumonia and its associated risk factors among under-five children visiting Merawi Primary Hospital, Northwest Ethiopia. A health center-based cross-sectional study was conducted among 403 participants by systematic random sampling technique. Data were collected by questionnaire survey, clinical diagnoses, and complete blood counting test laboratory diagnosis. The data was analyzed using STATA version 16 and descriptive statistics. All variables were used in the univariate logistic regression. To determine potential predictors of under-five pneumonia variables with p-values less than 0.25 were further considered for multivariate logistic regression and P-value < 0.05 at 95% The confidence interval was declared statistically significant. The overall prevalence of pneumonia among under-five children in the study area was 25.8%. Caring of child on mothers back or besides mother during cooking (AOR = 3.086 ; 95% CI: 1.540-6.211 ; P= 0.001), Using charcoal as source of fuel for cooking (AOR = 4; 95% CI: 1.675-9.523 ; P= 0.002 ), mixed breastfeeding (AOR= 3.884; 95% CI: 2.044-7.377; P = 0.000), children who were unvaccinated (AOR = 4.354; 95% CI: 2.018- 9.396; P = 0.000), children who did not get Vitamin A (AOR=4.204, 95% CI: 1.704-10.371; P=0.002), children who have had moderate acute malnutrition (AOR= 2.252; 95% CI: 4.065- 1.245 ; P=0.007), and children‘s family those who cook food in the living room at home (AOR=3.984; 95% CI: 1.779-8.929; P=0.001) were potential associated risk factors of under-five pneumonia. Therefore, discouraging the practice of carrying a child on the mother's back or keeping the child in close proximity to the mother during cooking activities, discouraging the use of charcoal as a fuel source and promoting use of electricity as a fuel source, monitoring the breastfeeding habit, increasing immunization and vitamin A supplementation,encouraging the use of kitchens are recommended. Keywords: Associated risk factors, Logistic regression, Prevalence, Under five-pneumonia