A comprehensive understanding of retroperitoneal lymphatic involvement is lacking in tumors of low malignant potential. This study was undertaken to evaluate retroperitoneal lymphatic involvement in patients with ovarian tumors of low malignant potential. One hundred seventy-one patients were diagnosed with epithelial ovarian tumors of low malignant potential between 1979 and 1989. Thirty-four (20%) of these patients underwent surgical staging which included lymph node sampling. The stage distribution was Stage I in 17 patients (50%), Stage II in 4 patients (12%), and Stage III in 13 patients (38%). The histology of the tumors was serous in 26 patients (76%), mucinous in 7 patients (21%), and seromucinous in 1 patient (3%). The incidence of retroperitoneal lymphatic involvement was 21%. The occurrence of positive pelvic and para-aortic nodes was 17 and 18%, respectively. Patients with localized intraperitoneal disease were upstaged in 22% of the cases based on retroperitoneal lymphatic involvement. Four of twenty-one patients (19%) with intraperitoneal disease confined to the ovary and two of six patients (33%) with intraperitoneal disease confined to the pelvis were upstaged to Stage III as a result of retroperitoneal lymphatic disease. Although the nodal status of patients did not significantly affect survival, those patients with localized intraperitoneal disease and nodal involvement had a higher incidence of recurrence which was statistically significant (P = 0.025). Accordingly, retroperitoneal lymph node sampling at the time of initial laparotomy may provide valuable prognostic information regarding recurrence in patients with tumors of low malignant potential.