Objective: To analyze the survival effects of upper abdominal procedures (UAPs) in patients with the International Federation of Gynecology and Obstetrics (FIGO) Stage IIIb to IV ovarian cancer stratified by initial presence of upper abdominal disease (UAD) and UAP performance. Materials and Methods: The authors retrospectively reviewed records of patients with FIGO Stage IIIb to IV epithelial ovarian cancer confirmed by pathology between January 2007 and December 2016 from the gynecologic cancer registry of Kangbuk Samsung Hospital. Results: During the study period, 74 patients with FIGO Stage IIIb to IV epithelial ovarian cancer underwent primary cytoreductive surgery. Among them, 28 patients had no UAD and no UAPs (group 1), 30 had UAD but did not undergo complete UAPs, especially without diaphragmatic resection (group 2), and 16 had UAD and underwent complete UAP including diaphragmatic resection (group 3). Except for age, most baseline characteristics did not vary among the three groups. In group 3, diaphragm peritonectomy was the most commonly performed UAP (93.8%), followed by liver resection (6.8%) with significant differences between groups 2 and 3 (p < 0.01). Five-year OS was 77.9% in group 1, 9.5% in group 2, and 76.7% in group 3 (p < 0.01). Median PFS was 37 months in group 1, 10 months in group 2, and 25 months in group 3 (p < 0.01). Conclusions: UAPs including complete removal of diaphragmatic lesions led to better survival outcomes for advanced-stage ovarian cancer.