From January 1978 to May 1979, the Chikungunya virus came out in several places in south of Central African Republic. We isolated one strain of virus from a human serum and 33 from pools of Aedes africanus group collected in two forest galleries situated near the village of Bozo, in the semi-humid savanna. Several serological conversions were observed in patients with fever joint pain and sometimes macular eruption. The intensive activity of Chikungunya virus was confirmed by serological survey in south-east of the country, i. e.: 17% sera were positive by IHA test with high level (greater than or equal to 1 280) according to recent infection. Mosquitoes strains isolated in 1978 seem to proceed from epizootic manifestation, as we observed in 1975 in the same area. Epidemiologic findings of periodic recurrence is discussed.