The objective of the present investigation was to study pharmacokinetics of promethazine in Korean healthy subjects using a validated HPLC method. The HPLC analysis was performed on a Capcell Pak CN column with a mixture of acetonitrile-0.02M potassium dihydrogen phosphate (42:58, v/v, pH 6.0) and the analyte was quantified with UV detection at 251 nm. The calibration curve of the drug was linear over the range of 1-40ng/mL in human serum and the limit of quantification (LOQ) was 1 ng/mL. This analytical method was validated and shown to be specific, accurate, precise and reproducible. This method was applied to pharmacokinetic study of promethazine in Korean healthy volunteers following an oral administration of two 25 mg Himazin tablets (50 mg promethazine ${cdot}$HCI) after overnight fasting. Serum samples were collected at given intervals over a 36-hour period (12 points) and pharmacokinetic parameters were determined from serum concentration-time profile using WinNonlin program. The estimated $AUC_{0__infty}$, $AUC_{0_infty}$, $C_{max}$, $T_{max}$ and $t_{1/2}$ of promethazine obtained from Korean healthy subjects were 103.84 ${pm}$84.30 ng${cdot}$hr/mL, 87.94${pm}$81.02 ng${cdot}$hr/mL, 13.43${pm}$10.92 ng/mL, 2.00${pm}$1.16 hr and 5.88${pm}$3.47 hr, respectively.