Hydatidosis is a parasitic disease caused by Echinococcus granulosus. It is also among the most prevalent zoonotic diseases with special importance for public health that causes drastic financial losses in both developed and developing countries. Among Algerian governorates, M’Sila region includes an important number of sheep flocks. Thus, an epidemiological survey was conducted on sheep hydatidosis during 5 months between December 2017 and April 2018 at three slaughterhouses of M’sila governorate, situated in municipalities of M’Sila, Boussaâda and Sidi Aissa. In parallel, an epidemiological investigation via interviews and questionnaire was conducted from March to April, 2018 on a sample of 46 sheep breeders located in M’Sila region. The questionnaire treated several risk factors (presence and deworming of dogs, informal slaughtering practices, fiability of preventive measures…etc.). Results showed a general prevalence of 24.80% among 9048 slaughtered sheep, and a seasonal prevalence higher in spring (42.02%) than in winter (21.65%) (p>0.05). Sheep of five to six years old and more are the most parasitized (p<0.0001). The lungs (38. 24%) and the livers (30.39%) were the most affected organs, while 31.24% of sheep were affected simultaneously in both organs (liver and lungs). Furthermore, females are more affected (97.99%) than males (2.01%) (p<0.0001).