In anaesthetized, mechanically ventilated, indomethacin‐treated pigs, we infused E. coli endotoxin (LPS, 20 micrograms kg‐1 h‐1, i.v.). After 150 min of endotoxaemia, 10 mg kg‐1 glibenclamide (an ATP‐sensitive K+ channel antagonist) was administered i.v. over 5 min. Vascular variables were recorded before (control), after 150 min of endotoxaemia and 5, 15 and 30 min after glibenclamide infusion. Glibenclamide transiently (within 5 min) increased systemic arterial pressure, reduced by LPS administration, without an effect on cardiac output. Our data indicate that ATP‐sensitive K+ channels may play a partial role in the vascular changes due to endotoxaemia.