OBJECTIVE: Digestive tract malformation is most common in neonatal surgical diseases, for which early surgery is required. The purpose of this study was to show the importance of perioperative biochemical monitoring in newborns. METHODS: Forty neonates with surgical diseases (digestive tract malformation accounting for 40%) aged 13.8±12.7 days were included in this study. Serum biochemical parameters, including blood routine, electrolytes and blood sugar were determined before and after operation. RESULTS: The white blood cell count was within normal range but the ratio of lymphocyte in the differential count significantly increased from 0.34±0.15 to 0.40±0.17 after operation ( P < 0.05 ). In contrast, the hemoglobin level decreased significantly after operation (from 142.11±33.09 g/L to 130.89±27.17 g/L, P < 0.05 ). The levels of serum Na+, K+ and Ca 2+ were not significantly different, while blood sugar contents increased significantly from 6.90±6.24 mmol/L to 10.20±6.89 mmol/L post-operatively (P < 0.05 ). CONCLUSIONS: Post-operatively, neonates may be prone to developing anemia and hyperglycemia. It is important to monitor the changes of biochemical parameters during perioperation.