A protocol for binding cresyl fast violet (CFV), a SERS-active dye (label) containing an aromatic amino group with a modified oligomer having a carboxy derivatized thymidine moiety using carbodiimide coupling has been achieved for the first time. Covalent coupling between CFV and the oligomer has been confirmed by mass spectral analysis of the labeled oligomer. The fluorescence, SERS and absorption characteristics of the labeled product have been evaluated. The chosen oligomer contains a BRCA-1 (breast cancer) sequence, and hence has the potential for being used as a gene probe to identify BRCA-1 gene. It has high potential for being used in polymerase chain reaction (PCR) amplification, as has been performed with labeled oligonucleotide for the HIV sequence.