Abstract: Electron impact ionization mass spectra of six new synthetic bis-piperazinium salts (M 2+ 2Br -2HCl) with anti-tumor activities were obtained. Although the M + ions and double charge ions M 2+ were not observed in EI mass spectra, some strange ions such as + ions, + ions , + ions, + ions and even + ions presented in EIMS by decreasing the electron energy. These phenomena may be explained as R + rearrangement and intermolecular reaction occurring in the condensed phase. We tried to describe the main routes of fragmentation and high sensitive mass spectra of the fragments oabout these compounds.