Five tricyclic antidepressants: imipramine hydrochloride, noxiptilin hydrochloride, hydroxyzine dihydrochloride, diethiazine hydrochloride and amitryptyline hydrochloride were determined by the capillary electrophoresis method. The determinations were performed by using a fused sillica capillary (60 cm x 50 microns i.d., effective length 53 cm). Acetate buffer (25 mM ammonium acetate and 1 mM acetic acid) in (1:1) methanol:water solution was used as an electrolyte. The determination voltage was 20 kV. The UV-detector at 214 nm was applied.