A capillary electrophoretic method (CE) with ultraviolet absorption detection for baclofen in human plasma was developed. The separation was obtained by CE with 50 mM borate buffer at pH 9, followed by detection with an ultraviolet detector at 225 nm. The plasma samples were deproteinized with acetonitrile to remove proteins and to induce sample stacking. With stacking, the limit of detection (LOD) for baclofen in plasma was 0.2 μM. A calibration curve ranging from 1.5 to 300 μM showed to be linear. Both the within-day and day-to-day reproducibility and accuracy were less than 15% and 8%, respectively. The recoveries of baclofen in human plasma were 99.6 – 103.3%.