Benzene, toluene and p-xylene are derivatives of benzene, generally produced from crude petroleum and have numerous applications in industry. The aim of the present study was to evaluate the impact of biofield treatment on isotopic abundance of these benzene derivatives by gas chromatography-mass spectrometry (GC-MS). Benzene, toluene and p-xylene samples were divided into two parts: control and treatment. Control part was remained as untreated and treatment part was subjected to Mr. Trivedi’s biofield treatment. Control and treated samples were characterized using GC-MS. GC-MS data revealed that isotopic abundance ratio of 13C12C or 2H/1H (PM+1/PM) of treated samples were significantly increased from un-substituted to substituted benzene rings (where, PM- primary molecule, PM+1- isotopic molecule either for 13C/12C and/or 2H/1H). The isotopic abundance ratio of 13C/12C or 2H/1H (PM+1/PM) in benzene was decreased significantly by 42.14% as compared to control. However, the isotopic abundance ratio of (PM+1/PM) in treated toluene and p-xylene was significantly increased up to 531.61% and 134.34% respectively as compared to their respective control. Thus, overall data suggest that biofield treatment has significantly altered the isotopic abundance ratio of (PM+1/PM) in a different way for un-substituted and substituted benzenes.