Background Little is known about the oncologic results of patients with low-grade endometrial stromal sarcoma (LGESS) with fertility preservation. This study was to investigate the prognosis of fertility-sparing surgeries and relevant obstetrical outcomes. Methods All eligible patients in the study center were retrospectively reviewed if they consented to surgical treatment for primary LGESS from February 2012 to June 2019 in the study center. Follow-up of fertility and oncologic outcomes was carried out until June 1, 2020. Results Among 135 patients accepted surgical therapy for primary uterine LGESS, 21 (15.6%) and 42 (31.1%) had fertility-sparing surgery and ovarian preservation, respectively. After a median follow-up of 38.5 (range 5-98) months, differences existed in the recurrent rates among patients with and without fertility-sparing surgery (47.6% versus 15.8%, p=0.002), or with and without ovarian preservation (42.9% versus 10.8%, p<0.001). Fertility-sparing surgery and ovarian preservation significantly increased the recurrent risks in the whole cohort (hazard ratio [HR] 3.5 and 5.2, 95% confidential interval [CI] 1.6-7.6 and 2.4-11.3, p=0.002 and <0.001) and in stage I patients (HR 2.6 and 3.1, 95% CI 1.0-6.4 and 1.3-7.4, p=0.041 and 0.011). No factor was found to be associated with increased mortality risk. Among 9 patients attempting pregnancy, 7 (77.8%) achieved 8 live births. Three advanced stage patients with fertility-sparing surgery all experienced recurrence without successful conception. Conclusion Fertility-sparing surgery for LGESS results in a significantly increased risk of recurrence but not of mortality, and has promising results in terms of live births in stage I patients.