Molecular detection of Cucumber mosaic virus in various chrysanthemum cultivars was attempted by RT-PCR and Southern hybridization tests using CMV specific primers and cloned probes, respectively. A pair of primers was designed from a conserved region of the Cucumber mosaic virus coat protein (CMV-CP) gene, capable of amplifying a product of ~650 bp from various CMV strains. RT-PCR using the total nucleic acid from infected leaf samples and the specific primers resulted in positive amplification of an expected size band of ~650 bp in most of the samples. The identity of the PCR amplicons was checked by Southern hybridization using the a32P-labelled DNA probes prepared from the cloned coat protein gene of a well-identified strain of CMV isolated from Amaranthus. Positive signal of hybridization of PCR products and CMV probes confirmed the identity of fected chrysanthemum samples.