ContextWhether venous catheterization at the femoral site is associated with an increased risk of complications compared with that at the subclavian site is debated.ObjectiveTo compare mechanical, infectious, and thrombotic complications of femoral and subclavian venous catheterization.Design and SettingConcealed, randomized controlled clinical trial conducted between December 1997 and July 2000 at 8 intensive care units (ICUs) in France.PatientsTwo hundred eighty-nine adult patients receiving a first central venous catheter.InterventionsPatients were randomly assigned to undergo central venous catheterization at the femoral site (n = 145) or subclavian site (n = 144).Main Outcome MeasuresRate and severity of mechanical, infectious, and thrombotic complications, compared by catheterization site in 289, 270, and 223 patients, respectively.ResultsFemoral catheterization was associated with a higher incidence rate of overall infectious complications (19.8% vs 4.5%; P<.001; incidence density of 20 vs 3.7 per 1000 catheter-days) and of major infectious complications (clinical sepsis with or without bloodstream infection, 4.4% vs 1.5%; P = .07; incidence density of 4.5 vs 1.2 per 1000 catheter-days), as well as of overall thrombotic complications (21.5% vs 1.9%; P<.001) and complete thrombosis of the vessel (6% vs 0%; P = .01); rates of overall and major mechanical complications were similar between the 2 groups (17.3% vs 18.8 %; P = .74 and 1.4% vs 2.8%; P = .44, respectively). Risk factors for mechanical complications were duration of insertion (odds ratio [OR], 1.05; 95% confidence interval [CI], 1.03-1.08 per additional minute; P<.001); insertion in 2 of the centers (OR, 4.52; 95% CI, 1.81-11.23; P = .001); and insertion during the night (OR, 2.06; 95% CI, 1.04-4.08; P = .03). The only factor associated with infectious complications was femoral catheterization (hazard ratio [HR], 4.83; 95% CI, 1.96-11.93; P<.001); antibiotic administration via the catheter decreased risk of infectious complications (HR, 0.41; 95% CI, 0.18-0.93; P = .03). Femoral catheterization was the only risk factor for thrombotic complications (OR, 14.42; 95% CI, 3.33-62.57; P<.001).ConclusionFemoral venous catheterization is associated with a greater risk of infectious and thrombotic complications than subclavian catheterization in ICU patients.