Since the first description of cognitive therapy of paranoid delusions appeared in the literature, the empirical support for cognitive behavioral therapy in treating psychotic symptoms has been widely established. The aim of the present case study is to show how the behavioral experiment can be used as a powerful tool to change delusional thinking in a patient with paranoid schizophrenia. In addition to highlighting the use of behavioral experiments to change the patient's delusion, we will illustrate various cognitive techniques that can be adapted to treat patients with psychotic symptoms. (Contains 2 tables and 2 figures.)