Several viruses, which in some cases can cause severe losses, affect carnation plants. These viruses include carnation mottle virus, carnation etched ring virus (CERV), carnation vein mottle virus, carnation ringspot virus, carnation Italian ringspot virus and carnation latent virus. A non-isotopic molecular hybridization was developed for the detection of these viruses in host plants and the sensitivity of the technique has been compared with enzyme-linked immunosorbent assay and bioassay methods. A procedure was developed to test simultaneously for the five RNA viruses (except CERV). The conditions established for this simultaneous detection did not include the DNA virus CERV due to the necessity of incorporating an additional step of RNase A treatment in the procedure to eliminate background signals. The sensitivity limits obtained for each virus using this multiple detection assay were identical to those obtained with the individual assays. The relative benefits of using this detection procedure for routine diagnosis of carnation viruses are discussed.