Over 100 different RNA modifications exist that are introduced posttranscriptionally by enzymes at specific nucleotide positions. Ribosomal RNA (rRNA) and transfer RNA (tRNA) exhibit the most and diverse modifications that presumably optimize their structure and function. In contrast, oxidative damage can lead to random modifications in rRNA and messenger RNA (mRNA) that strongly impair functionality. RNA modifications have also been implicated in avoiding self-RNA recognition by the immune system or immune evasion by pathogens. Here, we describe the detection of RNA modifications by HPLC analysis and competitive ELISA.