Water supply and sanitation sector corruption remains one of the most pervasive and the least confronted issues. Especially it becomes more devastating and serious in developing countries like Ethiopia. Therefore, study assess the current situation, depth, types and main causes of water supply and sanitation sector corruption in Jimma town. To this end, the study employed descriptive research design. This survey was conducted over 400 respondents in Jimma town using multistage stage sampling method. Personally administered questionnaires, interview and desk review were mainly used to collect both primary and secondary sources of data. The study reveals corruption remains problematic in the town water supply and sanitation sector. Especially administrative or petty corruption is the very common and become serious challenge in Jimma town water supply and sanitation service delivery. It is quite evident that time, cost factors and red-tape procedures are the major constraints in water supply and sanitation service delivery. Thus, setting systems and structures that can reduce incidences of corruption and ensure efficient delivery of services, use modern information communication technologies, awareness creation, support the participation of stakeholders, creation of strong cooperation between governmental and non-governmental actors, developing institutional anti-corruption strategy are highly recommended to fight against water supply and sanitation sector corruption.