Mean venous pressures were measured in 20 patients in whom a catheter, inserted via the external jugular vein, failed to pass centrally. The catheter used had a rounded end and two side holes. Pressures were measured with the patient's head in three different positions. The pressures were compared with the central venous pressures measured from a catheter inserted through an antecubital vein (and confirmed to be placed centrally). In all patients the differences between the mean pressures from the two sites were all within 3 mm Hg and were not influenced by alteration in head position or the side of jugular catheterization.