We report the case of a 69-year-old man with acute pulmonary echinococcosis. A computed tomographic scan of the thorax revealed the presence of multiple nodules in both lungs, and laboratory tests showed eosinophilia and the presence of antibodies against Echinococcus granulosus. Therapy with albendazole led to resolution of the pulmonary nodules and a normalization of the white cell count. To our knowledge this is the first described case of acute echinococcosis, as the diagnosis of this disease is usually delayed to chronic phases. Therefore, finding unexplained eosinophilia, especially in association with pulmonary nodules, should lead one to suspect acute hydatid disease.