The safety and efficacy of ketazolam (15 mg capsules) was compared to placebo in seventy-nine out-patients suffering from psychoneurotic anxiety, moderate or worse in severity. A flexible dosage range of 15-75 mg was used in this double-blind study lasting twenty-eight days. The average optimum therapeutic dose of ketazolam was 46-9 mg administered as a once-day dose at bedtime. Ketazolam was found to be significantly better than placebo in alleviating anxiety and its concomitant symptomatology as measured by the Hamilton Anxiety Rating Scale, three Physician's Global Impressions, two Patient's Global Impressions, and three Target Symptoms. Fifteen patients dropped from the placebo group before completion of the study, and two withdrew from the ketazolam group. The patients receiving ketazolam experienced a greater reduction in symptomatology throughout the study when compared to the placebo group. Side-effects experienced by the ketazolam patients were less than, or equal to, the placebo patients. No deleterious side-effects occurred. No differences between the two groups were found for vital signs, EKG's, laboratory tests, or physical examinations.