PURPOSE OF THE STUDY: The aim of this study was to evaluate the influence of obstructive sleep apnea (OSA) in children on maternal and paternal anxiety. PATIENTS AND METHODS: This prospective study was conducted from January 2013 until January 2016 in the Ear, Nose and Throat (ENT) Department at the University Hospital of Split, Croatia. The parents of 59 children with a median age of 5 years (range: 2-9) who were suffering from obstructive sleep apnea (OSA) due to adenotonsillar hypertrophy were enrolled into the study. All children were scheduled for adenoidectomy or adenotonsillectomy because of airway obstruction. In addition, their parents completed the 20-item State-Trait Anxiety Inventory-1 (STAI-1) and 20-item State-Trait Anxiety Inventory-2 (STAI-2) questionnaires before the operation and 30 days after the surgery when their children had considerable improvements in breathing during their sleep. The STAI is an instrument that quantifies both state (STAI-1) and trait (STAI-2) anxiety. State-Trait Anxiety Inventory-1 (state anxiety) is intended to measure transitory anxiety at a specific time (related to OSA symptoms in our study), whereas STAI-2 (trait anxiety) measures long-term anxiety. RESULTS: Overall, the study included 57 mothers and 53 fathers of 59 children diagnosed with OSA. The mean preoperative STAI-2 score of parents was 31.1 ±â€¯7.5; for fathers it was 28.2 ±â€¯6.3, and for mothers it was 33.7 ±â€¯7.6. The STAI-1 and STAI-2 scores showed significant differences before and after the surgery according to gender. The mean score of mothers was 5.5 (95% CI: 2.8 to 8.1) higher than the mean score of fathers (t = 4.1, p < 0.001) on the STAI-2 scale. The mean score of mothers was 5.6 (95% CI: 0.48 to 0.7) higher than the mean score of fathers (t = 2.2; p = 0.032) on the preoperative STAI-1 scale. The mean score of mothers was 1.95 (95% CI: 0.35 to 3.6) higher than the mean score of fathers (t = 2.4; p = 0.017) on the postoperative STAI-1 scale. The mean score of mothers was 6.22 higher than the mean score of fathers (p = 0.029) on the preoperative STAI-1 scale, adjusted for the STAI-2 scale. The mean score of mothers was 1.8 higher than the mean score of fathers (p = 0.039) on the postoperative STAI-1 scale, adjusted for the STAI-2 scale. These data suggest that differences between the preoperative and postoperative STAI-1 score for mothers was the highest (51 ±â€¯7) in children with severe OSA and the lowest (28 ±â€¯14) in children with mild OSA (p < 0.001). The difference between the preoperative and postoperative STAI-1 score for fathers was the highest (48 ±â€¯6.6) in children with severe OSA and the lowest (25 ±â€¯10) in children with mild OSA. CONCLUSION: The results of our study suggest that obstructive sleep apnea in children is a disturbing symptom for parents and is associated with a significant level of anxiety that depends on OSA severity. After the surgical treatment of the children (adenoidectomy or adenotonsillectomy), the anxiety level of both parents decreased. We suggest that preoperative psychological intervention should be considered in selected cases for mothers and fathers of children with severe OSA in order to diminish the symptoms of anxiety that can compromise normal postoperative recovery in operated children.