Beyond genomics, transcriptomics and proteomics, metabolomics is a powerful tool which is considered to be the next step for a comprehensive illustration of biological pathways in organisms. The metabolic profile (the expression levels of metabolites) reflects the final physiological state in response to biotic and abiotic stimulation. Moreover, metabolites act as messengers and are intimately entwined with cell signaling between individuals and species. Therefore, the qualification and quantification of small molecules using metabolomics has gained interest. Academia Sinica Metabolomics Core Facility (ASMCF) was founded in 2009 to support the demand for metabolomics analyses. We provide services for mass spectrometry-based metabolomics analysis. Both targeted, predefined candidates, and untargeted, also referred to as global metabolite profiling, analyses are provided. With advanced instruments, the liquid chromatography coupled with high resolution-mass spectrometry, we can provide a highly accurate and highly sensitive metabolite profile even for complex biological samples.