Leaf samples were collected from 138 tomato (Lycopersicon esculentum) plants showing symptoms of Cucumber mosaic virus (CMV) in the north-west Mediterranean region of Turkey. The samples were first tested by double antibody sandwich-enzyme linked immunosorbent assay (DAS-ELISA) using CMV specific polyclonal antibody. The DAS-ELISA revealed that 53 of the 138 leaf samples tested were infected with CMV. One of the ELISA-positive CMV isolates was mechanically inoculated into a set of indicator plants by conventional leaf inoculation method for further characterisation. The virus was multiplied and showed systemic symptoms in Nicotiana tabacum `Xanthii', Nicotiana tabacum 'Samsun NN', and Capsicum annuum. Double-stranded RNA (dsRNA) was isolated from uninfected and infected N. tabacum 'Xanthii' and C. annuum plants by CF-11 cellulose chromatography. Agarose gel electrophoresis showed that CMV-specific dsRNA was present in infected N. tabacum 'Xanthii', Nicotiana tabacum 'Samsun NN', and C. annuum plants but not in healthy plant samples. This result agreed with the biological and serological findings and confirmed the presence of CMV on tomato growing in the northwest Mediterranean region of Turkey.