question: BACKGROUND: Although efforts have been made by the international community to improve childhood health, risk factors linked with the healthiness of preschool-age children in low and middle-income countries (LMICs) are very diverse. Therefore, this paper examines the prevalence and determinants of fever, acute respiratory infection and diarrhea of preschool children in Bangladesh. METHODS: A sample of 8,421 children from the latest country representative BDHS-2017–18 survey was analyzed by utilizing both the bivariate and multivariate techniques. RESULTS: The results revealed that about 4.7, 33.1, and 35.8% of the children aged under 5 years had suffered from diarrhea, fever and ARI respectively during the 2 weeks preceding the date of the survey. Demographic, socio-economic, and community and health characteristics likely to play an important role in suffering under-five children from diarrhea, fever, and ARI in Bangladesh. The child’s age of 13–24 months, delivery by cesarean section, unsafe drinking water, unhygienic toilet facility, low level of family wealth index and parental education, a higher number of living children in the household, rural residency and regional difference were all found to be most crucial determinants of the occurrences of fever, ARI and diarrhea. CONCLUSION: Interventions should focus on improving these significant demographic, socioeconomic, and community and health risk factors. A special attention is necessary to the people who live in rural areas and geospatially disadvantaged regions.