In Argentina hydatidosis is a serious problem of Public Health with socioeconomic effects Strong urbanistic populational streams brought from the country local habits to urban areas. Hydatidosis became them an urban zoonosis. In spite of data on canine infection found (1.12%) are lower than those found in rural areas from the same region, the potential capacity to infect humans is higher in dogs from areas of high demographic density. The high incidences of human infections found are in accordance with this idea.