Both during and after cancer treatment, pyogenic spondylitis is an uncommon but serious complication. Because pyogenic spondylitis is often recognized as a complication of a distant process causing bacteremia, it initially may be misdiagnosed the primary infection such as urinary tract infection. Consequently, a considerable delay in diagnosis frequently occurs. In addition, estrogen deprivation caused by cancer treatments including RT/CCRT, CT and surgical therapy promotes changes of the immune system. We report two cases of pyogenic spondylitis in a patient with vaginal cancer that occurred delay of the diagnosis, and in a patient with endometrial cancer that had chronic steroid use, and one case of suppurative osteomyelitis in a patient with vulvar cancer that had diabetes mellitus with obesity. Gynecologic oncologists must consider the diagnosis of pyogenic spondylitis based on clinical symptoms such as localized lumbago and medical history. Estrogen deprivation, repeated cancer treatment, diabetes mellitus with obesity, immunosuppression by chronic steroid use are risk factors of pyogenic spondylitis. To prevent delay in diagnosis of pyogenic spondylitis, it is necessary that we must have careful management and follow-up considering all of information such as clinical features and medical history on patients during and after treating for gynecologic malignancies.