Infection-specific, nonstructural, African swine fever virus antigens, as visualized by the immunofluorescence technique, appeared as fine stipplings, evenly distributed in the cytoplasm and nucleus of Vero cells and in monocytes by postinoculation hour (PIH) 3. Cytoplasmic inclusion bodies (IB) appeared at PIH 4 and continued to increase in size up to PIH 8. The viral DNA was solely synthesized within the IB of infected monocytes, as evidenced by an autoradiographic chase experiment; maximum synthesis occurred at PIH 5. The 2,300-S and 2,500-S (sedimentation coefficient) structural viral antigens were visualized in the IB at PIH 5 and 6, respectively. The infective new progeny of African swine fever virus were formed between PIH 7 and 8, and the cell surface viral antigens were produced between PIH 8 and 9. Free virus was released between PIH 10 and 11. Infected cells detached from the glass surface from PIH 13. The 5-iodo-2'-deoxyuridine interfered with the formation of infective virus, but not interfere with the production of viral antigens.