Ribosomal RNAs (rRNA) are conserved, abundant species-specific sequences that are used for phylogenetically classifying organisms. Due to their abundance and species specificity, rRNA sequences have been established as optimal targets for in situ hybridization (ISH). ISH for rRNA sequences using DNA oligonucleotide probes has been utilized to detect a variety of fungi in paraffin tissues. However, ISH with some oligonucleotide DNA probes produces weak signals, and applications for nucleotide modification may be useful to enhance hybridization signal. ISH with LNA probes has been shown to result in improved ISH signal. A protocol for LNA ISH with biotin-labeled LNA oligonucleotide probes is described.