We examined in this perspective study 30 patients (15 males and 15 females) who undergone classic thoracotomy for lung or mediastinal diseases, without postoperative complications. Intensity and different qualitative components of postoperative pain have been evaluated in the 1st, 3rd, 5th, the day after last pleural drainage removal and 2 months after the operation. All patients answered a schedule adherent to Questionario Italiano del Dolore (QUID). Pain became less intense chiefly with drainage removal with the same time trend for both sex (parallel curves). Pain is probably stronger in women. From a qualitative point of view, the sensorial component is the same in both sexes. Affective and evaluative component is greater in women: in other words, women realize more than men the painful stimulus and are more troubled. A computerized analysis of answers to a questionnaire like QUID or, better, its evolution, may be helpful for a more effective pharmacological choice between pure analgesics, sedative analgesics and ataractic drugs.