In the Tanzanian water and sanitation (WatSan) sector, the human resource (HR) requirements for meeting the Millennium Development Goal (MDG) targets have so far been relatively unknown. This study was therefore conducted with a focus on determining HR requirements in the public sector and parastatal institutions, in the private sector (private consultancy companies, individual contractors, etc.), and in non-governmental organizations and community-based organizations active in the broader water, sanitation and hygiene (WASH) sector. The competences assessed were: design and construction of new infrastructure, operation and maintenance (O&M), community mobilization, sanitation, and hygiene promotion. The study found a greater HR shortage in rural areas than in urban areas. The smallest HR need is for social development professionals (estimated at 320 in the urban areas). In the water supply and sanitation sectors, the average number of water supply engineers that will be required to achieve MDGs is estimated at 3,864, compared to the sanitation sector, which will need 637 engineers. In terms of the demand for competences in the water supply sector, the highest need is for O&M professionals (7,589) and the lowest for mobilization professionals (447). The study recommends increasing the HR supply in the WatSan sector through the following measures: increasing support for training institutions offering relevant courses in WatSan; focusing on skills required for asset management and O&M; and giving specific attention to HR capacity development in small towns and rural areas.