A capillary electrophoretic method for the determination of cetirizine is described in this study. The method was developed by using a running buffer consisting of 10 mM of 10% methanol with pH 8.5, employing a fused silica column with a total length of 85 cm, an effective length of 65 cm, and internal diameter of 75 mu m. 28 kV were applied, which produced signals that were detected at 200 nm. Under these conditions, cetirizine and phenobarbital sodium as an internal standard appeared at 6.7 and 8.9 minutes, respectively. The limits of detection and quantification were found to be 5.45 x 10(-6) M and 1.60 x 10(-5) M, respectively. The repeatability and linearity of the method were validated by intra-day and inter-day precision. Then, the proposed method was applied to Zyrtec trademark tablet, syrup, and oral drop. The results indicate that the method is simple, accurate, and precise for the analysis of cetirizine.