The fragmentation of Oligopeptide samples were investigated using electrospray ionization masss spectrometry. All three peptide samples were fragmented and studied under both positive and negative ion mode. The software used for the investigation of individual peaks and fragmentation of selected precursor ion was done through Bruker Daltonics Data Analysis 3.4. Through the analysis, it was found that peptides 1 and 3 are more suitable to be studied under positive ion mode, while peptide 2 under negative ion mode due to its acidic nature in which deprotonation of the compound is more likely to occur. The survival yield was calculated for each increasing collision energy level and plotted for comparison in case of all the peptide samples.