This study draws on purposive survey data of approximately 600 households in peri-urban Tanzania to describe the degree and nature of non-farm diversification in these settings. With the exception of relatively dynamic cities such as Dar es Salaam and Arusha, overall non-farm incomes shares are not unambiguously higher than in rural areas as a whole. Non-farm income shares rise sharply and monotonically with quintiles defined in terms of per capita food consumption. In that sense the sector appears to offer an important route out of poverty. The evidence suggests that education, and access to infrastructure, are important determinants of non-farm incomes in peri-urban areas. Women appear to be poorly placed vis à vis the non-farm sector, even after controlling for education, age and other characteristics. Kinship and tribal affinities, and time devoted to communal activities, appear to deter entrepreneurial activity and non-farm employment, but trust in officials and public servants and strong heterogeneous village associations, are important in stimulating non-farm activity.