The authors have determinated the medium-size diameter of the Schistosoma's granuloma during its many forms of evolution (necrotic - exsudative, produtive and recovery by scarring) in 332 cases of human hepatic schistosomiasis. Within those studied cases three were 167 in the acute, toxemic form and 167 the cronic form (hepato-splenic and disseminated). The 286 measured granulomas were studied from needle-biopsy material in the acute form and 165 from surgi cal and needle-biopsy in the latter.