The curcuminoids are a group of diarylheptanoid molecules that possess important pharmacological activities, particularly acting as anti-inflammatory agents. The main purpose of this study was to investigate the fragmentation behavior of the three major curcuminoids in ion trap liquid chromatography/tandem mass spectrometry (LC/MS/MS). Both positive and negative mode electrospray ionization in tandem and multidimensional MSn experiments in quadrupole ion trap instruments and high-resolution and accurate mass MS and sustained off-resonance irradiation (SORI) MS/MS experiments in a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer were used to elucidate the main fragmentation channels of these compounds. These experiments yielded essentially the same fragmentation results in both ion trap and ICR instruments for all three curcuminoids and for their phenolic monoacetates. Major and diagnostic fragment ions were identified and their origins are proposed. Copyright © 2006 John Wiley & Sons, Ltd.