Abstract This paper deals with the impact of rainfall‐index insurance on the adoption of new varieties of durum wheat by Tunisian farmers. We use a mathematical programming model called ‘focus‐loss’ to determine the optimal production of four representative farms in the region of Beja, in the northwest, with rainfall‐index insurance and without rainfall‐index insurance. Results show that the expected net incomes are higher under with rainfall‐index insurance scenario. Furthermore, for the latter, optimal production structures include new varieties of durum wheat. Copyright © 2013 John Wiley & Sons, Ltd.