The aim of the present study was to evaluate the curative effect of fludeoxyglucose-positron emission tomography/computed tomography (F-18-FDG-PET/CT)-guided intensity-modulated radiotherapy (IMRT) for 42 patients with International Federation of Gynecology and Obstetrics (FIGO) stage III/IV ovarian cancer. Between January 2012 and December 2015, 42 patients with FIGO stage III/IV ovarian cancer who were treated with F-18-FDG-PET/CT-guided IMRT at the Department of Radiation Oncology were analyzed. A total of 21 patients who exhibited recurrence following surgery and 11 patients who were unable to tolerate or rejected surgery received 5-10 cycles of chemotherapy only. A total of 10 patients, who were either older (>70 years) or in poor general health were unable to undergo surgery and only received IMRT. The patients received a total radiation dose of 5,040 cGy (range, 4,500-5,500 cGy), with a dose fraction of 200 cGy/fx, administered a total of 10-14 times, 5 times/week, prior to being rested for half an hour to relocate lesions and undergoing a second round of radiotherapy for 10-14 cycles. The 1-, 2- and 3-year progression-free survival (PFS) rates of the patients were 66.7, 33.3 and 21.4%, respectively, and the median PFS time was 20.3 months. The 1-, 2- and 3-year local control rates of the patients were 90.5, 83.3 and 69.0%, respectively, and the 1-, 2- and 3-year overall survival (OS) rates were 73.8, 64.3 and 52.4%, respectively. According to the results of multivariate analysis using the Cox proportional hazards model, the Karnofsky performance status (KPS) score (1) was the only index associated with prognosis (P<0.003). The study concluded that for patients with advanced ovarian cancer, particularly for patients unable to undergo surgery or chemotherapy, F-18-FDG PET/CT-guided IMRT is a safe and effective treatment method, and it may be considered as an equally effective treatment option. Furthermore, the results of the present study suggested that the KPS score of a patient is the only factor affecting the OS time.