Abstract: A gas chromatographic method for the determination of nifedipine in human plasma is presented. Nifedipine was extracted into toluene and diazepam was used as the internal standard. Chromatography was performed on an OV-101 fused silica column by splitless injection with an electron capture detector. The minimal detectable concentration in plasma was 1 ng·ml ^-1. The standard curve was linear in the range 2～150 ng·ml^-1 (γ=0.9988). The method has been applied to pharmacokinetic study.