Between February 1999 and December 2003, 691 hair samples were extracted, amplified, and sequenced. Of these, 593 were questioned hairs (85.8 percent), and 98 were known reference hairs (14.2 percent). Full mtDNA profiles were obtained on 570 hairs (82.5 percent), and partial profiles were obtained on 71 hairs (10.3 percent); no profile was obtained on 50 hairs (7.2 percent). Overall, at least partial data were obtained on 92.8 percent of analyzed hairs. Hairs from which no profile was obtained often had a history of extreme environmental exposure. Hair masses exposed to the environment in missing persons cases are rarely successful in analysis when the mass has been recovered after months or years. This paper thus recommends that skeletal material be used preferentially in a body identification, even if hair is available. The population of hairs included in this study is more representative of the range of conditions that may challenge a laboratory's protocols than any validation study created to simulate extremes of testing. Retrospectively, the ability to obtain profiles in the majority of cases shows that the protocols are valid and efficient. Combined with the application of quality controls, quality assurance, validation studies, and proficiency testing, this paper advises that a laboratory using these or similar protocols will provide optimal services to the forensic community. 2 tables, 6 figures, and 20 references