Three cucumber mosaic virus (CMV) isolates from local virus populations were characterized. Mechanical inoculation of the CMV isolates to Chenopodium quinoa (Willd), and Vigna unguiculata (L. Walp) TVu 76 induced local infections of chlorotic spots and necrotic spots only on the inoculated leaves. Similar systemic infections including mosaic and leaf distortion and vein clearing symptoms were induced on Cucumis sativus L., Datura stramonium L. and Capsicum annuum L. and six other Nicotiana species used.Nicotiana glutinosa L. appeared to be the only host upon which the isolates reacted differently. Immunosorbent electron microscopy showed the virus as a 29 nm diameter isometric virus. The protein molecular weight was 29,000 daltons in polyacrylamide gel electrophoresis analysis. When coat protein gene of the virus was amplified by reverse-transcriptase polymerase chain reaction using a pair of CMV-specific primers, approximately 500 base pairs were obtained. Restriction enzyme digests of the amplified products with Msp1 and EcoR1 endonuleases revealed that all three CMV isolates belonged to subgroup I.