A viral aetiological and epidemiological study of acute respiratory infections (ARI) in children was carried out in Lusaka, Zambia between June 1993 and September 1995. A total of 3760 throat swab specimens were collected for virus isolation from children under 5 years of age who had ARI and were attending three health centres in Lusaka. Between June and November 1993, 52 cases of the influenza A/H3N2 viruses were isolated. Between May and July 1994, 34 influenza B cases were isolated. In 1995, one A/H3N2 influenza virus was isolated in January and then the same type of influenza virus was isolated from 55 samples between June and August. The isolation rate of influenza virus was highest at 14.3% (20/139) in August 1993, at 15.1% (18/119) in June 1994 and at 25.4% (43/169) in July 1995. This is the first report of a consecutive study of influenza virus infections in Zambia and the results reveal that influenza virus infections are one of the most important pathogens of ART in children in the cool, dry season (June-August) in this country.