We determined an optimal electrolyte system for isotachophoresis (ITP) with conductivity detection of citalopram, fluoxetine, fluvoxamine and sertraline. The analysis conditions were applied to the determination of these selective serotonin re-uptake inhibitors in antidepressant drugs. It is shown that capillary ITP with conductivity detection is a simple and quick method for the determination of citalopram, fluoxetine, fluvoxamine and sertraline in drugs.