Although cognitive-behavior therapy (CBT) is a relatively new psychotherapeutic approach, the theoretical antecedents actually date back two thousand years, to the period of the hellenistic philosophers. The Stoic Epictetus is often acknowledged as the main philosophical father of CBT and especially of rational-emotive therapy (RET). Beck and Ellis frequently noted that they have drawn upon the writings of the ancient philosophers in developing their psychotherapeutic techniques. This paper reviews some implications of hellenistic philosophy for CBT. We like to show that the teachings of the ancient 'healer of souls' are remarkably consistent with the current theoretical framework and techniques of CBT.