A placebo-controlled double-blind clinical trial on the effect of niaprazine on children with some common sleep disorders was carried out. Niaprazine at a daily dosage of 1 mg/kg body weight or placebo at random was administered to a selected group of 36 children (aged from 6 months to 6 years) suffering from frequent nighttime waking or inability to fall asleep. The effect of niaprazine (or placebo) on sleep disorders was studied by means of continuous home-videorecorded sleep before and after the trial. A reliable positive effect of niaprazine on the sleep disorders considered was found. No adverse side effects were observed. We conclude that niaprazine seems to represent an effective and safe drug for the therapy of frequent nighttime waking and inability to fall asleep.