The authors made 106 cultures from the endings of intravenous catheters used in children hospitalized in the teaching hospital in the years 1987-88. In 30 cases (28%) the cultures were positive. The most common cultures were those of Staphylococcus and Micrococcus. No correlation was found between the time of keeping a catheter in the vein and the number of positive cultures from the catheter. The children not receiving antibiotics had 2.6 as many positive cultures as those receiving antibiotics.