This invention relates to antibodies to complexes formed between PNA (Peptide Nucleic Acid) and nucleic acids, particularly antibodies to PNA/DNA or PNA/RNA complexes. The preferred antibodies are polyclonal, monoclonal and recombinant antibodies that binds to PNA/DNA or PNA/RNA complexes, but not to single-stranded PNA, double-stranded nucleic acid or single-stranded nucleic acid. Peptide Nucleic Acids (PNA) are newly developed, not naturally occurring compounds comprising a polyamide backbone bearing a plurality of ligands such as naturally occuring nucleobases attached to a polyamide backbone through a suitable linker. PNA oligomers with a backbone of N-(2-aminoethyl)glycin units have a surprising high affinity for complementary nucleic acid forming very stable and specific complexes. This property makes PNA oligomers suitable as hybridization probes for detection of nucleic acids. The usability of PNA as hybridization probes is greatly increased by the present antibodies. The antibodies according to the invention are useful in the capture, recognition, detection, identification or quantitation of nucleic acids in biological samples, via their ability to react with PNA-nucleic acid complexes.