Background: The authors used the lipid index (WL) to monitor lipid changes before and after surgery. The surgical operation performed was the simultaneous enucleation of a cystic tumor of the hilum ovarii in its entirety (with diagnosis of a simple cyst or teratoma adultum) in groups of 20 patients. Objectives: To compare the lipid index WL in the blood serum of patients undergoing surgery treatment at the following times: before and 7 days after surgery, and 6 and 12 months after surgery. Material and methods: The research material was the blood serum of women aged about 24 years. The authors divided the patients into 3 groups: two groups of 20 women and a control group. The concentrations of the lipid parameters were measured and the lipid index WL was calculated. Results: Statistically significant differences were found between the lipid index of serum from patients with diagnosed ovarian neoplasms and the index of serum from healthy subjects; differences were demonstrated in the postoperative period, particularly 6 and 12 months after surgery. Conclusions: The lipid index WL proved useful in diagnosing ovarian neoplasm (simple cysts and teratoma adultum) and in monitoring the postoperative period.