The analysis of compounds from veterinary sources has employed traditional wet chemistry, immunoassay and chromatographic methods. These older methods are valuable in classifying unknown compounds. With these tools and the guidance of a veterinary pathologist it is possible to narrow the focus of a chemical search to a particular class of compounds. Current requirements for lower detection limits, identification and confirmation require the use of mass spectrometry detection in order to provide legally defensible data. Two hyphenated techniques that meet these requirements are Gas Chromatography-Mass Spectrometry (GC-MS) and Liquid Chromatography-Mass Spectrometry (LC-MS). Tandem mass spectrometry (MS/MS or MS2) offers even greater sensitivity and selectivity to provide the highest confidence in small molecule analyses. The future will include greater reliance on Time-of-Flight (TOF) and Fourier Transform (FT) mass spectrometry. Several of these instruments are currently available which incorporate higher mass resolution and software to "de-convolute" mass spectral information to identify unknowns. These techniques are financially out of the reach of many labs. However, just like LC-MS was once viewed as an exotic technique, so too will these state-of-the-art instruments come down in price as the technique gains more widespread acceptance.