The oil-soft wax fraction of the microcrystalline wax, extracted from the Bombay High crude tank bottom sludge (Indian origin), has been characterized using gas liquid chromatography (GLC), H-1 and C-13 nuclear magnetic resonance (NMR), and gas liquid chromatography-mass spectroscopy (GLC-MS). A series of saturated acyclic isoprenoid hydrocarbons have been identified in this wax. These structures have been confirmed by recording GLC-MS spectra of the oil-soft wax fraction at reduced ionization potentials of 30 and 20 eV and also recording the spectra of two known available standards, namely, pristane and phytane.