Full text article. Also available at http://dx.doi.org/10.5897/AJEST09.207A vulnerability assessment of rain fed agriculture to climate change and variability in semi-arid parts of Tabora Region in Tanzania was conducted in 2009. Four village clusters were selected out of which, three villages represent Millennium Villages Program (MVP) namely Mbola, Mpenge and Isila from Uyui District. One village namely Tumbi from Tabora Urban bordering the MVP was also selected. Both primary and secondary data were collected using different methods including structured questionnaire interviews, focus group discussion, documentary review and field observations. Structured questionnaire interviews were administered to 7% of all farmers selected at random from the four villages and 30 research and extension officers obtained through accidental purposeful sampling. Simple regression and t-test analyses of numeric data for rainfall and temperature collected over the last 35 growing seasons were performed using Microsoft Excel and Statistical Analysis System respectively. Non-numeric data were coded, summarized and analyzed using Statistical Package for Social Sciences spreadsheet. Results indicate that the overall rainfall amount was found to decline while distribution was varying both in time and space. Inter-seasonal dry spells between January and February appeared to increase both in duration and frequency. Temperature has shown an increasing trend. Minimum temperature increased faster (R2 = 0.68, p<0.001) while maximum temperature increased gradually (R2 = 0.24, p<0.01). Farmers, research and extension officers also perceived these changes by the help of a series of indicators. Nevertheless, perception on the climate change indicators varied depending on the type of livelihood activity most affected. Major implications on rain fed agriculture are possible shrinking of the growing season, increasing moisture and heat stress to common food and cash crops, increased insects and pests and eventually low income and food insecurity. This study concludes that there is strong evidence demonstrating the vulnerability of rain fed agriculture to negative impacts of climate change and variability in the study area. It is suggested that there is a need for multi-level interventions on adaptation to climate change and variability taking into account a wide range of stakeholder involvement.