Splenectomy or distal pancreatectomy (DP) is sometimes performed for optimal cytoreduction in advanced ovarian cancer (AOC). In particular, it is considered to remove tumors involving the splenic hilum or the capsule of the spleen to secure tumor-free margins sufficiently. For splenectomy, the gastro-splenic ligament is opened, and the short gastric vessels are dissected. After the splenocolic ligament and splenic flexure of the colon are transected, the peritoneal attachments, including the splenorenal and splenophrenic ligaments, are divided to mobilize the spleen, and then the splenic artery and vein are identified and ligated separately. If DP is needed for en bloc resection of tumors, a linear cutting stapler is used to remove the tail of the pancreas, and suture reinforcement with 2-0 or 3-0 prolene on the cut section of the pancreas is performed to prevent postoperative pancreatic fistula (POPF). Immunization with a polyvalent pneumococcal vaccine is required after splenectomy to avoid overwhelming post-splenectomy infection (OPSI) caused by Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae. If POPF occurs after splenectomy or DP, continued drainage with close monitoring is needed with the administration of board spectrum antibiotics in grade A or B POPF according to the criteria of the International Study Group of Pancreatic Fistula (ISGPF). In contrast, grade C POPF requires aggressive management using nothing by mouth, total parenteral nutrition, and somatostatin analogs, and sometimes reoperation if deteriorating signs such as sepsis and organ dysfunction. Thus, the effort for preserving pancreatic tail is needed to reduce hospitalization and the risk of POPF despite the minimal impact of DP on the success rate of optimal cytoreduction.