In a simple way, metabolomics aims at reporting which metabolites and how much are in the biological samples. In targeted metabolomics identification and quantification of preselected metabolites is straightforward because authentic standards of particular compounds are used. Such an approach is usually limited to tens of metabolites. On the other hand, during an untargeted metabolomics experiment annotation of hundreds or even thousands of small molecules and reporting the results is more challenging. Merging untargeted analysis with a targeted approach promises to provide not only the data for the discovery of novel metabolites but also quantitative data for validation. Quantitative data are crucial to enable direct comparisons of the results between different laboratories and clinical studies. In this presentation, approaches toward standardization in clinical metabolomics will be presented along with practical examples.