To test the hypothesis that the incidence of central venous catheter-related complications is increased in very low (< 1000 gm) and low (1001 to 1500 gm) birth weight infants compared with larger infants, we retrospectively analyzed the charts of 51 infants with gestational ages 24 to 42 weeks, weighing 0.43 to 12.2 kg at catheter insertion, who had 69 catheters placed at 1 week to 11 months of age between January 1986 and June 1989 at our hospitals. The incidence of infectious and mechanical complications and the frequency of total and infection-related complications were significantly greater for infants weighing < 1000 gm at catheter insertion (p < 0.05). Oxacillin-resistant coagulase-negative Staphylococcus organisms accounted for 14 of the 17 episodes of catheter-related septicemia (82%). Six of these episodes were initially treated with antibiotics but without catheter removal; none resolved with catheter salvage. Central venous catheters in very low and low birth weight infants had an 85% and 64% incidence of associated complications, respectively, and should be used with caution in these patients.