Morphine, codeine, and hydromorphone were extracted from blood or serum using a one step extraction. The extract was derivatized and the trifluoroacetyl opiates were quantified by GC/MS selected ion monitoring (SIM) using nalorphine as the internal standard. Calibration curves were linear and sensitivity as low as .02 mg/L for morphine and codeine, and .08 mg/L for hydromorphone, was achieved. Urine or tissue homogenates could be processed similarly after acid hydrolysis.