Intraabdominal hypertension (IAH) develops frequently in patients with septic shock. Even a moderate increase in intraabdominal pressure (IAP) in this setting could be associated with high lactate levels. The authors conducted a prospective, observational, nonrandomized control trial in the surgical intensive care unit of an academic tertiary center. Twenty-seven patients with septic shock (septic shock group), and 19 patients undergoing abdominal surgery with more than two risk factors for IAH (postoperative control group) were admitted consecutively to the intensive care unit. IAP was measured every 6 hours during the first 48 hours. IAH was diagnosed with two consecutive measurements greater than 20 mm Hg. The main outcome measures were prevalence of IAH in septic shock and control groups; and comparative lactate levels, norepinephrine requirements and organ dysfunctions in patients with and without IAH in both groups. Fifty-one per cent of patients with septic shock and 31 per cent of control patients developed IAH. Patients with septic shock with and without IAH were comparable in peak norepinephrine dose, sequential organ failure assessment score, and mortality. However, peak lactate levels were significantly higher in patients with septic shock and IAH compared with those without IAH (3.5 mmol/L versus 1.9 mmol/L, P < 0.04). There was a significant positive temporal correlation between IAP and lactate levels in patients with septic shock with IAH. Peak levels of both occurred early and decreased progressively over time. Control patients with and without IAH exhibited comparable peak lactate levels. Intraabdominal hypertension is very common in septic shock and appears to be related to high lactate levels, which diminish as IAP decreases. Future studies should address the usefulness of IAP monitoring in patients with septic shock.