Catheter-related bacteremia (CRB), along with liver failure is the leading cause of mortality and morbidity in parenteral nutrition dependent children. Immunosuppressant therapy following transplantation increases the risk of CRB. Previous reports in pediatric cancer patients have described the use of antibiotic lock solutions (ABL) for prophylaxis of CRB. In our institution, we evaluated five children (ages between one and four yr old), three with intestinal transplantation and two with short gut syndrome, who were high risk for recurrent CRB defined by their incidence of bacteremias in the observation period (>2 CRB/six months or life-threatening CRB). These children received the prophylactic ABL protocol with tobramycin-tissue plasminogen activator, four h per day, on alternating ports for six to eight months. Each patient was his/her own historical control. We observed decreased incidence of CRB's (p < 0.05), days of hospitalization due to CRB's (p < 0.0001), the days of intensive care admissions due to CRB (p < 0.0001), as well as the total days of systemic antibiotic exposure (p < 0.001). Catheter survival during the ABL era was longer but not reaching statistical significance. There was no advantage in removing and later replacing the catheter to wire-guided exchange while on systemic antibiotics. One patient presented with break-through bacteremia, septic shock and died. None of the catheters were lost to occlusion/malfunction. ABL did not induce an increased resistance to tobramycin. These preliminary findings suggest that ABL can be used safely and effectively in parenteral nutrition dependent children with long-term central venous catheters.