Accelerated soil erosion is one of the major constraints to agricultural production in many parts of the Tanzanian highlands. Although several soil and water conservation technologies have been developed and promoted, the adoption of many recommended measures is minimal and soil erosion continues to be a problem. This research was conducted in order to determine the social and economic factors that influence adoption of soil and water conservation (SWC) measures in the West Usambara highlands, Tanzania. For this research a household survey, group discussions and transect walks were undertaken. A total of 104 households were interviewed and several fields were visited during the transect walks. Data was analysed with the use of cross-tabulation, cluster analysis, factor analysis and chi-squared methods. The results obtained indicate that involvement in off-farm activities, insecure land tenure, location of fields and a lack of short-term benefits from SWC are among the major factors that negatively influence adoption of SWC measures. Membership in farmer groups, level of education, contacts with extension agents and SWC programmes were found to be positively influencing the adoption of SWC measures. Recommendations to facilitate adoption of different SWC measures include: integration of social and economic factors into SWC plans; the creation of more awareness among farmers of soil-erosion effects and long-term benefits of SWC; the development of flexible SWC measures to cater for different farm patterns and a participatory approach to SWC at catchment level rather than at individual farmers' fields.