Infrared spectrometer (IR) conditions used for the analysis included one/centimeter point-to-point resolution as nujol mulls on sodium chloride disks. Suspensions of testosterone were extracted with chloroform, and the extract evaporated for IR or diluted to 0.2 milligram(mg)/milliliter(ml) for gas chromatography (GC). The testosterone esters were dissolved in vegetable oil, extracted with methanol, and at the same concentrations were injected into a capillary column GC or into a gas chromatograph(GC)-mass spectroscopy. The GC column temperature program was 250 degrees Centigrade for 2 minutes, 10 degrees/minute to 300 degrees, then held at 300 for 8 minutes. The injector and detector temperatures were 315 Centigrade. The carrier gas was helium with a flow rate of 1 ml/minute (min). The IR spectra of testosterone and the 11 esters were distinguishable from each other. Testosterone exhibited the ketone band at 1670/centimeter (cm), while the esters exhibited the ketone ban from 1660 to 1670/cm and the ester ban at 1735 to 1750/cm. Under these GC conditions, testosterone and the 11 esters exhibit baseline separation with the exception of testosterone undecanoate and testosterone undecanoate which appear as a merged peak. 27 figures and 11 references