Adductomics studies are used for the detection and characterizationof various chemical modifications (adducts) of nucleic acids and proteins.The advancements in liquid chromatography coupled with high-resolutiontandem mass spectrometry (HRMS/MS) have resulted in efficient methodsfor qualitative and quantitative adductomics. We developed an HRMS-basedmethod for the simultaneous analysis of RNA and DNA adducts in a singlerun and demonstrated its application using Baltic amphipods, usefulsentinels of environmental disturbances, as test organisms. The noveltyof this method is screening for RNA and DNA adducts by a single injectionon an Orbitrap HRMS instrument using full scan and data-independentacquisition. The MS raw files were processed with an open-source program, nLossFinder, to identify and distinguish RNA and DNA adductsbased on the characteristic neutral loss of ribonucleosides and 2 & PRIME;-deoxyribonucleosides,respectively. In the amphipods, in addition to the nearly 150 putativeDNA adducts characterized earlier, we detected 60 putative RNA adducts.For the structural identification of the detected RNA adducts, theMODOMICS database was used. The identified RNA adducts included simplemono- and dimethylation and other larger functional groups on differentribonucleosides and deaminated product inosine. However, 54 of theseRNA adducts are not yet structurally identified, and further workon their characterization may uncover new layers of information relatedto the transcriptome and help understand their biological significance.Considering the susceptibility of nucleic acids to environmental factors,including pollutants, the developed multi-adductomics methodologywith further advancement has the potential to provide biomarkers fordiagnostics of pollution effects in biota.