Metabolomics technology, employed in the analysis of low-molecular endogenous metabolites (e.g., by NMR, LC/MS, GC/MS) and with statistical algorithms, has been applied to the development of new drugs, the diagnosis of diseases, and a variety of other fields. In the present research, certain endogenous metabolite candidates with which, by application of metabolomics to forensic science, post-mortem changes can be inferred were postulated. We combined UPLC/Q-TOF MS-based metabolomics with a statistical analysis to search for metabolite changes related to the post-mortem interval. Metabolites extracted from the livers of rats 0, 24, and 48 h post-sacrifice were analyzed by UPLC/Q-TOF MS. After acquiring the exported UPLC/QTOFMSdata, PCA, PLS-DA, OPLS-DA andRwere applied to identify the significantly up/down regulated metabolites. Comparing the postulated metabolites list with the Human Metabolome Database (HMDB: http://www.hmdb.ca), we could classify samples for post-mortem-interval prediction.