A sensitive reversed-phase high-performance liquid chromatographic method for the determination of atevirdine and its primary metabolite in human saliva or cerebrospinal fluid using solid-phase extraction is described. Samples mixed with internal standard and sodium phosphate buffer were applied to an activated C18 solid-phase extraction column. The reconstituted eluate was injected onto a Zorbax RX C8 column utilizing a mobile phase of 100 mM ammonium acetate (pH 4.0)-isopropyl alcohol-acetonitrile (55:20:25, v/v/v). Fluorescence detection was employed with excitation at 295 nm and emission at 456 nm. Quantitation was achieved using peak-height ratios. The detection response curve was linear from 2 to 850 nM for atevirdine in both human saliva and cerebrospinal fluid and from 2 to 250 nM for the metabolite in human saliva. The method was utilized to analyze cerebrospinal fluid and saliva samples from clinical studies.