Diarrheal diseases remain one of the major global public health problems and a leading cause of morbidity and mortality in low- and middle-income countries like Bangladesh. Though the diseases are preventable and could be managed with low-cost interventions, the morbidity due to diarrheal diseases remains stable and has become the top causes of hospitalization of Bangladesh. Therefore, significant resources are consumed for treating patients with diarrhea. Among all of the diarrheal diseases, cholera and rotavirus are mainly responsible for severe diarrhea while endemic cholera is one of the largest burdens for Bangladesh.Vaccination is the most cost-effective investment for preventing the spread of vaccine-preventable diseases; Bangladesh is also committed to introduce cholera and rotavirus vaccination in the national Expanded Program on Immunization (EPI) schedule. This thesis investigates the health and economic burden of diarrheal diseases in Bangladesh and intends to generate evidence for policymakers about future nationwide cholera and rotavirus vaccination programs which have been inadequately studied.To achieve this aim, I have conducted a series of empirical studies for assessing the prevalence, economic burden of diarrheal diseases, economics of cholera vaccination, demand for cholera vaccines and the cost-effectiveness of future childhood rotavirus vaccination. The thesis is based on seven papers while five of them are primary survey-data driven and two of them are based on secondary data sources and modeling.As cholera and rotavirus infections are life-threating conditions to high-risk people and children, the thesis sort out that such preventive programs could avert a substantial number of cases, deaths, and hospitalizations and appeared as a cost-effective investment. The thesis is also point out that there is a lack of good quality information on disease incidence, mortality, and the economic burden in the country. Therefore, further research is needed for proper understanding for priority setting in diarrhea control. The thesis also highlights the potential demand for cholera vaccines in the community; therefore, individuals may not wait for the public vaccination campaign if the vaccines are available in private market.I believe that my thesis is provides a better understanding of the economics of diarrheal diseases and will contribute to the decision-making process regarding the prevention of diarrheal infections by strengthening the case for future oral cholera and rotavirus vaccination program in Bangladesh for the benefit of society.