Our aim is to evaluate whether outcomes differ by admission day of the week in patients with spontaneous pneumothorax. One hundred twenty five patients undergoing video-assisted thoracic surgery(VATS) in Fukuoka Tokusyukai Hospital from 2007 through 2011 for spontaneous pneumothorax were reviewed. The clinical characteristics and outcomes were compared between patients in weekend admission and weekday admission groups. Patients were divided in 2 groups based on admission between Monday thru Friday vs on Saturday or Sunday. Another 2 groups by admission between Sunday thru Thursday vs on Friday or Saturday were also examined. Time to operation was significantly shorter for admission on period between Sunday thru Thursday compared to admission on Friday or Saturday. But there was no difference in the other clinical factors and postoperative outcomes between 2 groups. Patients admitted on the weekend proved to experience delayed operation, but did not have increased adverse outcomes or longer length of hospital stay compared to those admitted on a weekday. No significant "weekend effect" for spontaneous pneumothorax was demonstrated by the present study.