African Swine Fever (ASF) is prevalent in Angola. It is caused by several strains of viruses, among which Silva-Porto and Huambo 85. A clinical and anatomo-pathological comparative test carried out on the natural and experimental disease showed different and significant characteristics in the behaviour of these two strains. Silva-Porto generates clinical signs characterized by an haemorrhagic generalized diathesis more marked on the skin, organs and viscera. In addition, the anatomo-pathological lesions are more severe and obvious than those caused by Huambo 85. This difference of intensity in the clinical development and the heterogeneity in the anatomo-pathological lesions depend not only on the previous physiological status of the animal, but also on type or breed susceptibilities and on the strains themselves and the biological specificities of each virus involved.