Neopterin is elevated in infections, autoimmune diseases and post-transplant. Recently neopterin elevation was linked to stress response and malignancy. To determine early changes of serum neopterin caused by surgical stress and to investigate their association with other inflammatory markers and with malignancy, we measured neopterin, C-reactive protein (CRP) and procalcitonin (PCT) levels at four predefined time-points within 24 hours in 27 patients admitted for liver resection. Our results show that neopterin increased during operation and the increase was not related to preoperative neopterin levels. On the first day after surgery neopterin level was not significantly different from postoperative levels. In patients with malignant disease neopterin concentration before operation was higher than in patients with non-malignant disease, however, the increase in neopterin concentration during operation was not different between both patient groups. During surgery CRP and PCT did not increase significantly. On the first postoperative day CRP and PCT were elevated and their levels correlated with neopterin (Pearson's correlation coefficient r=0.51 and r=0.76, respectively). We conclude that neopterin elevation during liver resection contributes major part to the increased levels observed on the first postoperative day. Perioperative neopterin release can/may be related to stress response and hypoxia produced during operation. Using this marker, hypoxic reperfusion damage could be detected earlier and more accurately.