MassBank is the first public repository of mass spectral data for sharing them among scientific research community. MassBank data are useful for the chemical identification and structure elucidation of chemical comounds detected by mass spectrometry. MassBank system is originally designed for public sharing of reference mass spectra for metabolite identification. It is also useful for their in-house or local sharing. Recently it finds another application; sharing mass spectra of unknown metabolites for metabolite profiling Registration not required.