A high performance liquid chromatographic assay was developed for determination of the plasma concentration of hexamethylene bisacetamide (HMBA) in rabbit. Plasma samples were vortex-mixed with 0.3 ml of methanol and centrifuged at 10000 r/min for 5 min. A 20 microliters aliquot of the supernatant was injected into the HPLC system. Analysis was performed on a Du Pont Zorbax C18 column (250 mm x 4.6 mm, 10 microns) with a precolumn (50 mm x 4.6 mm, 10 microns, YWG-C18). The eluent was methanol--water (30:70), with flow rate of 1.0 ml.min-1 and UV detection at 210 nm. The limit of detection was 1.0 microgram.ml-1 in plasma and the calibration curve was linear over the range 5-1000 micrograms.ml-1 (r = 0.9988). The HPLC assay was applied for studying the pharmacokinetics of HMBA in rabbit.