The separation and identification of morphine and codeine from postmortem blood and bile was accomplished using a liquid-phase extraction method followed by reversed-phase high-performance liquid chromatography with combined UV and fluorescence detection. Identification of morphine and codeine was based on relative retention time matching with calibration standards, together with their fluorescence-to-UV response ratios. Linear calibration curves for morphine and codeine ranged from 0.10 to 3.0 mg/L for blood and 5.0 to 100 mg/L for bile. Morphine concentrations (in autopsy cases), where the intravenous use of heroin or morphine was suspected as the cause of death, were 0.10-0.89 mg/L (mean, 0.29 mg/L) for blood and 3.3-112 mg/L (mean, 38 mg/L) for bile. Codeine concentrations, where therapeutic use or overdosage of codeine occurred, were 0.06-6.4 mg/L (mean, 1.5 mg/L) in blood and 0.22-89 mg/L (mean, 24 mg/L) in bile. This method allowed simultaneous detection of morphine and codeine from blood and bile with little interference from extraneous peaks. The procedure described provides a selective, sensitive, accurate, and reliable method suitable for both clinical and forensic toxicology.