This talk will review recent results on DNA oligonucleotide binding at surfaces and in solution. Using surface plasmon resonance spectroscopy for unlabeled oligonucleotide probes and solution oligonucleotide target species, we examine how the kinetics and thermodynamics of apparent binding for DNA/DNA hybridization depends on strand secondary structure, mismatches, and probe attachment chemistry. We show how SPR imaging can be used for quantitative monitoring of the kinetics of drug/DNA binding for an intercalating drug (actinomycin-D) interacting with array surfaces presenting multiple DNA target sequences containing different drug binding sites. SPR imaging is also used for optimization of attachment chemistry and for development of convenient surface coatings that resist non-specific binding of the pentapeptide containing drug. The array results are compared with solution phase measurements and other non-array SPR measurements and discussed in the context of chemical reaction mechanisms.