Since 1994 "Réseau VEGA" (veterinary survey network) has organized a record of sanitary information in 14 slaughterhouses in the Midi-Pyrénées. Data about hydatidosis in cattle are centralized, analysed, then sent namely to each stockbreeder concerned. Estimation of the prevalence rate from 1994 to 1996 is 0.28% for animals and 2.5% for livestock. A marked decrease of rates was noticed during this three year monitoring period. Nevertheless, the Pyrenean area remains more affected than the North of the region. In an outbreak of hydatidosis, a few animals are carriers. Bovine infestation must be considered as revealing a rural cycle. Moreover, the link between bovine hydatidosis and ovine transhumance seems to be confirmed. Using livestock as epidemiological units is innovative in terms of hydatidosis. This approach allows a better adjustment of parasitism control and introduces the notions of the outbreak and the risk of human contamination. In the Midi-Pyrénées region, local human cases of hydatidosis are few. However, the absence of compulsory notification and of databases, on the one hand, and the extreme difficulty of confirming the autochthonous nature of the contamination, on the other hand, limit the reliability of data. A better collaboration between physicians and veterinarians would reduce animal prevalence and the risk of human contamination.