This document analyzes the economic viability of jatropha curcas L. plantations in northern Tanzania by assessing costs and benefits via a cost-benefit analysis. It examines data from existing jatropha farms in three regions of northern Tanzania to determine production costs and yields. A net present value analysis of a 5-year investment reveals that jatropha cultivation results in a negative net present value when yielding 2000 kg per hectare but a slightly positive net present value when yielding 3000 kg per hectare. The analysis concludes that jatropha is not economically competitive with alternative crops on fertile land in northern Tanzania under current conditions."