Aims/Background. The proportion of patients who experience anxiety prior to planned surgery, even a minimally invasive one, is estimated at 50-70%. Thoracic surgery, causes significant preoperative anxiety, especially in children. The aim of this study was to determine the effect of an important component of psychological preparation for a surgery as information support on levels of anxiety, pain and satisfaction with postoperative analgesia. Methods. The randomized double blind study including patients aged 9-18 years qualified for lateral thoracotomy or Ravitch procedure. The subjects were randomized to the control group (n=56) provided with a routine preoperative information by a nurse, and the experimental group (n=56) offered additional psychological consultation. Data were collected via the State-Trait Anxiety Inventory. Results. In the experimental group, the level of state anxiety at 48 h post-surgery was significantly lower than prior to the procedure, but only in subjects with preoperative trait anxiety <7/10 sten. In the control group, the level of postoperative anxiety was significantly higher than prior to the surgery; this effect was observed irrespectively of preoperative trait anxiety level. Lack of preoperative psychological consultation (β=-0.23), trait anxiety ≥7 sten (β=0.25), and higher level of preoperative state anxiety (β=0.65) were independent predictors of greater state anxiety at 48 h post-surgery. Patients from the experimental group did not differ significantly from the controls in terms of their median pain scores and satisfaction with postoperative analgesia. Greater state anxiety was associated with 22% lesser likelihood of complete satisfaction with the analgesia. Conclusion. Information support from a psychologist offered prior to a thoracic surgery decrease the level of postoperative state anxiety solely in children with lower levels of trait anxiety. Higher level of postoperative state anxiety negatively affect patients' satisfaction with post-surgical analgesia.