We have reported the synthesis of comb type bDNA where a unique, primary oligonucleotide fragment is tailed with several identical copies of a secondary oligonucleotide1. The strategy for synthesis of these molecules is based on the use of a nucleoside analog branching monomer. Recent improvements in solid phase methods enable the synthesis of bDNA with as many as 50 copies of secondary sequences. Characterization of these bDNA is also discussed.