Autopsies of 61 infants under one year of age with catheterization of subclavian veins revealed in 27 cases complications of catheterization found both isolated and in various combinations. Their nature and frequency differed from those in adults. Noteworthy was a large number of hematomas of anterior mediastinum and parietal thrombi of the right atrium. Severe complications due to the penetration of the catheter into the pleural cavity or to hear perforation were more frequent. Among catheterization complications, emboly of vessels of the greater circulation through patent oval fenestra is possible. The occurrence of severe infectious complications in some cases is associated with the unobservance of the existing contraindications. The high frequency of complications observed at autopsies must be considered in deciding for indications for subclavian vein catheterization in infants under one year of age.