Fluorescence resonance energy transfer has facilitated the development of a new class of high-performance fluorescent labeling reagents for multiplex analyses of nucleic acids. The enhanced emission of energy transfer (ET) primers has provided a decadic improvement in the performance of automated DNA sequencers, The emission spectral purity of ET primers permits the development of robust multiplex diagnostic methods for the detection of PCR products. High affinity bifunctional intercalation reagents containing ET-coupled dyes are also being used for high-performance multiplex assays of double-stranded DNA when noncovalent labeling is preferred.