The study on contribution of valley bottom cultivation (vinyungu) to poverty alleviation in Mtitu River Basin in Kilolo District was conducted in order to examine the role of this type of agriculture to rural livelihood. This type of agriculture has been practiced over many decades. In Mtitu River Basin almost all valley bottoms are used by small farmers who practice farming in lowlands, usually called vinyungu, a type of farming practiced in dry season. Tanzania Government has been restricting agricultural activities that are carried along rivers, in catchments and in all valley bottoms, but still many areas of this type are used for agricultural activities. The specific objectives of this study were: (i) To investigate agricultural activities in Mtitu river Basin, (ii) to examine the importance of valley bottom cultivation (vinyungu) to people’s income, (iii) to examine why people prefer vinyungu and (iv) to assess the sustainability of valley bottom cultivation in the context of environmental conservation. Data were collected through structured, semi- structured questionnaires, Focused Group Discussion (FGD) and non-participatory observation. Purposive, stratified and simple random sampling were employed to obtain the respondents for vinyungu. These were eight villages with 15 respondents each village comprising a total of 120 respondents. Data processing and analysis were done at SUA using Statistical Package for Social Sciences computer software in conformity with the objective of the study. Research findings have revealed that contribution of valley bottom cultivation to income poverty in Mtitu River Basin in Kilolo District is beneficial to farmers when compared to upland farming. This is so because what the individual farmer earned per year was large as compared to cash income obtained from upland farming. In order to make vinyungu sustainable as a form of agriculture the farmers should follow all regulations set by the Kilolo District Council and the Rufiji Basin Water Office in Iringa.