To describe findings of deep venous thrombosis (DVT) in association with femoral central venous catheter (CVC) placement for intensive fluid management in children with diabetic ketoacidosis (DKA) secondary to type 1 diabetes. Retrospective cohort study. Pediatric intensive care unit (PICU) of a children's referral medical center. DKA patients from 1998 to 2002 of children with DKA with and without CVC placement. DKA patients were also compared with all PICU patients with CVC. CVC DVT was defined as ipsilateral leg swelling with CVC placement, confirmed by radiographic study, and persisting after CVC removal. Of 113 DKA PICU patients, 6 (5.3%) required femoral CVC for initial management. Three of these DKA/CVC patients developed ipsilateral DVT within 48 hours of CVC placement. All 3 patients required long-term therapy with low molecular weight heparin for persistent leg swelling. DKA/CVC patients with DVT were younger (median age: 10.5 months) than DKA/CVC patients without DVT. The number of DKA/CVC patients with DVT (1.4%) was significantly greater than for all femoral non-DKA/CVC patients. DKA/CVC patients were also significantly more likely to have DVT than age-matched shock/CVC patients. They also had significantly higher glucose, corrected sodium concentrations, and lower pH and serum bicarbonate than did age-matched shock/CVC patients. Femoral CVC placement is infrequently needed in pediatric DKA patients but can be associated with DVT. Femoral CVCs should be avoided in DKA patients or removed as soon as possible. DVT prophylaxis should be considered if a CVC is required.