Abstract Disclosure: S. Korpaisarn: None. T. Ngaothepphurktharam: None. Y. Tingthanatikul: None. Background: Gynecological neoplasm/malignancy is one of the concerned areas among transgender men on masculinizing hormone therapy (MHT). Long-term MHT and gynecological neoplasm/malignancy remain unclear. Methods: A retrospective cohort chart review was done on all transgender men (TM) who underwent hysterectomy with or without oophorectomy between January 2014 and October 2022. Intraoperative findings and pathological results of genital organs, including the cervix, endometrium, myometrium, and fallopian tubes, were extracted. The pathological results were classified as benign, precancerous, and malignant. Descriptive statistical analysis was used to demonstrate the prevalence of gynecological neoplasm and malignancy. Results: A total of 30 TM underwent hysterectomy with oophorectomy. Twenty-eight (93%) had bilateral oophorectomy, and 7% had unilateral oophorectomy due to gynecological conditions. The mean age when TM underwent surgery was 32.1 ± 5.1 years, and the mean age of gender-affirming hormone initiation was 28.7± 5.1 years. The median duration of MHT before gynecological surgery was 32 months (IQR 22-59). Most TM (73%) used testosterone enanthate, 17% testosterone undecanoate, and 2 transgender men did not start MHT before genital surgery. All TM who used GHT became amenorrheic before surgery. The median preoperative testosterone level was 561.5 ng/dL (IQR 776-1189). Intraoperative findings revealed that most TM (86.7%) had unremarkable uterus size, and 13% showed enlarged uterus size. In the latter, all were from myoma uteri. Most intraoperative findings of ovaries showed 93% unremarkable. One TM had intraoperative polycystic ovarian morphology, and one showed a unilateral ovarian cyst. Cervical pathological reports showed unremarkable results in 67%. Five TM (17%) had chronic cervical inflammation. There was 1 TM (3%) who showed low-grade squamous intraepithelial lesion (LSIL) with squamous metaplasia. Regarding endometrial pathology, the mean endometrial thickness was 0.13 ± 0.08 cm. Most endometrial reports (66%) were in a proliferative phase, 27% were in an atrophic or inactive endometrium, and 7% were in the secretory phase. Regarding pathological reports of ovaries, 80% had cystic ovaries. None of the TM showed precancerous or malignant conditions of endometrium, ovaries, and fallopian tubes. PAP smear was available in 27 TM; all were negative for intraepithelial lesions or malignancy. Conclusion: Among a cohort of TM who received MHT for 32 months, there is no evidence of precancerous or malignant pathology of the endometrium, ovaries, and fallopian tubes. Most of them had thin endometrium with cystic ovaries. One TM showed LSIL with squamous metaplasia of the cervix. Healthcare providers should follow local gynecological cancer screening guidelines developed for cisgender women in their clinical practice. Presentation: 6/2/2024