Fever and myalgia are non-speciflc clinical manifestations of illness which commonly occur in patients with arboviral disease. In Egypt, such illness is often mis-diagnosed as ''influenza'' . To determine arbovira! aetiology in patients admitted with fever .and myalgia, acute and convalescent sera samples were obtained from 55 patients admitted with these clinical manifestations to the Imbaba Fever Hospiral, Giza, Egypt, during October and November I984. Based on viral isolation, and a comparison of acute and convalescenr sera, 4 patients (7%) had acute arboviral infections. Haemagglutination inhibition and indirect immunofluorescencc tests showed that one had West Nile virus infection, 2 had sandfly fever virus-Naples (SFN), and 1 had sandfly fever virus-Sicilian (SFS) infection. SFN was isolated from the acute serum sample of 1 of the 2 patients with SFN infection.