An estimation of relative risk of resurgence of bovine tuberculosis (BTb) in previously infected herds and free of disease strengthened the decision of total depopulation according to 1999 french regulation (OR ~80). However, this value did not give information of the risk for such herds to become infected twice. Data from French Ministry of Agriculture has been used for an estimation of incidence rate cumulated for several years. Numerator was number of re-infected herds previously infected and free of BTb, for which resurgence was supposed to be responsible. Denominator was estimations of herds at risk. According to different calculation ways, values of cumulative incidence rates and cumulative incidence risks were about 2 per cent (range 1.5%; 2.5%). Validity of estimations is discussed, as the interest of these estimations for the decision for some herds and in some conditions to stop total depopulation.