This paper analyzes the choice of contractual forms in tax collection activities. It draws on historical data from the world as a whole to illustrate the factors involved in the choice among wage, share and fixed rent (tax farming) techniques. This is followed by a detailed analysis of tax farming as applied to Tunisia's periodic markets so as to explain the continued reliance on this otherwise generally abandoned form of tax collection in this particular sector. Finally, some implications for policy in both developed and developing countries are derived.