Objectives: To determine the short-term effects of adjuvant or primary curative radiotherapy (RT) on the urinary system in women with gynecologic cancer. Material and methods: This is a prospective, concurrent cohort study including 55 patients with gynecologic cancer who were divided into three groups. Group 1 included 10 patients who were administered adjuvant RT following a radical hysterectomy (RH); Group 2 included 36 patients who were administered adjuvant RT following a type 1 hysterectomy and Group 3 included 9 patients who were administered primary curative RT. Urogynecologic assessments were carried out on patients before and six months after the treatment. Results: Compared to pretreatment, no significant differences were observed in any of the three groups after treatment in terms of incontinence, first urge to urinate, normal urge to urinate, severe urge to urinate and changes in residual urine volumes. There was a significant decrease in maximal vesical pressure after treatment in Group 1 and Group 3. The maximum detrusor pressure decreased significantly in Group 1. The post-treatment decline in bladder capacity in Group 1 and Group 2 was also significant. Conclusions: RH and pelvic RT cause lower urinary system dysfunction. Especially patients who receive primary curative RT and patients who are administered RT after RH, where more pelvic denervation occurs, are at higher risk due to high doses of RT.