Purpose: Interstitial brachytherapy (ISBT) is often used as post-external beam radiotherapy (EBRT) to treat locally advanced gynecological malignancies. Female urethra is in close proximity to the target during ISBT. However, it has not been evaluated as an organ-at-risk (OAR). Overlapping symptoms caused by radiation-induced bladder toxicity vs. urethral toxicity make it difficult to identify and report urethral toxicities separately. This was a retrospective study to estimate dose-volume parameters of female urethra during high-dose-rate ISBT.Material and methods: Data of 24 patients with gynecological malignancies treated by ISBT were selected. Urethra and periurethral regions were retrospectively contoured. Mean volume, D max , D mean , D 2cc , D 1cc , D 0.5cc , D 0.2cc , and D 0.1cc were documented. Unpaired t-test was used for comparison of means.Results: 20/24 Ca. cervix, 1/24 Ca. vagina, and 3/24 Ca. vaginal vault received 6-6.5 Gy in 4 ISBT fractions. Mean urethral length was 3.54 ±0.55 cm. Mean doses received by urethra per BT fraction were D max = 4.23 ±1.32 Gy, D mean = 2.71 ±1.01 Gy, D 0.2cc = 3.31 ±1.07, and D 0.1cc = 3.54 ±1.09 Gy. Comparison of total BT 2 Gy equivalent dose (EQD 2 ) with 4 fractions for urethra between patients with (9/24) and without anterior vaginal wall (15/24) involvement included D mean