Cantharidin is mainly found in the beetle families Meloidae and Oedemeridae (Insecta: Coleoptera) which are the natural producers of this terpene anhydride. Most studies to date have focused on cantharidin distribution in blister beetles, with few reports on recently found cantharidin-related compounds (CRCs). Using gas chromatography-mass spectrometry (GC-MS), the present work reported cantharidin and two CRCs, palasonin and cantharidinimide from Mylabris impressa stillata (Baudi, 1878) which was collected from Toyserkan county, Hamedan Province, Iran. Ionization provided mass spectra with characteristic fragments of cantharidin at m/z 96 and 128, demethylcantharidin at m/z 82 and 114, and cantharidinimide at m/z 70, 96 and 127. This is the first time that cantharidin and the two CRCs are found in the genus Mylabris which in turn is new to the field of venomous insects