Opiates were extracted from sixteen hair samples of drug addicts using a supercritical fluid extraction method with supercritical carbon dioxide and a modifier solution of methanol-triethylamine-water (2:2:1, v/v). the concentrations, as determined by GC-MS, ranged from 1.22 to 21.73 (mean 7.60 ng/mg), 0.17 to 1.54 (mean 0.69 ng/mg) and 0.15 to 14.009 ng/mg hair (mean 3.78 ng/mg) for codeine, morphine and 6-monoacetylmorphine, respectively. The reproducibility of the total procedure had a relative standard deviation of 13%, 17% and 14% for codeine, morphine and 6-monoacetylmorphine, respectively. But this method, concentrations of 0.3, 0.2 and 0.1 ng/mg hair for codeine, morphine and 6-monoacetylmorphine, respectively, could be detected. Relative extraction recoveries were 61%, 53% and 96% for codeine, morphine and 6-monoacetylmorphine, respectively.