The concept of imprisonment as a primary punishing technique was brought to Tanzania from Europe together with the capitalistic mode of production (which presently dominates) by British and German colonialists. During the colonial era the prison seved as a coercive instrument of State power, and as such was the primary sanction in the process by which the wage-earning native labor force was created and controlled. In addition, prisoners were utilized as a source of labor for building public utilities. Since independence (1961), the emphasis has been on rehabilitation of prisoners through learning skills concentrated in agriculture, the basis of Tanzanian economy. Prison labor is being deployed on a nation-building and revenue-sharing footing, with some penal institutions being declared as economically self-sustaining corporations. The modern agricultural practices implemented there are intended to serve as models for village agriculture. The aim of rehabilitation, however, is illusive, since persons are incarcerated for adherence to forbidden tribal customs, for default of agricultural production norms, and for noncompliance with mandatory resettlement in villagization projects. As more and more offenders are sent to prisons for openly opposing government policies, the institutions are failing their economic self-sustenance goals and becoming an increasing burden to the State. The contradictory conditions in Tanzanian prisons reflect the conflict between the government's aims to create a socialist society and ideological consensus out of a reality where capitalist characteristics dominate the economy and primintive customs guide the populace. Illustration, references, and statistical data are included.