Life-threatening hypophosphatemia has been reported after major liver resections with a significant impact on postoperative outcome. Regeneration of the liver may play a crucial role, but the underlying mechanism has not yet been elucidated. This study aims at assessing the effect of vascular control and resected volume of the liver on postoperative phosphorus levels. The study included 30 patients that underwent liver resection. Sixteen patients were operated on without any vascular control and 14 with selective vascular exclusion. Correlation between serum kinetics of phosphorus to resected liver volume and warm ischemia was carried out. All patients experienced low postoperative phosphorus levels. The lowest levels were observed on the second postoperative day, when 40% developed life-threatening hypophosphatemia (< or = 1.1 mg/dl). Warm ischemia and major resections aggravated hypophosphatemia compared with patients operated on without vascular occlusion and with those with minor resections. Vascular exclusion and major resections aggravate hypophosphatemia. Patients who developed hypophosphatemia < or = 1.5 mg/dl were more prone to complications and longer hospital stays compared with counterparts who had serum phosphorus levels > or = 1.6 mg/dl.