Forensic science has benefited greatly from the many advantages that are inherent with infrared microspectroscopy. First of all, microspectroscopic techniques require only a small amount (down to a picogram or below) of sample for analysis. In addition, infrared microspectroscopy is a non-destructive technique. Both of these advantages make infrared microspectroscopy ideal for any sample which is available in a limited quantity, such as evidence in forensic investigations. This application note will discuss the infrared microspectroscopic analysis of one particular type of forensic sample: hair fibers.