Mature ovarian dermoid cysts (ODCs) are the most common benign ovarian tumors diagnosed in children. However, there is minimal data on management of ODCs in premenarchal patients. This study assesses characteristics associated with expectant (EM) vs surgical (SM) management in premenarchal patients and the growth rate of ODCs in EM patients at a single institution. Forty-four premenarchal patients, either post-surgical with pathologically-confirmed ODC or having radiologic findings consistent with ODCs, were included. Data collected included demographics, cyst characteristics, imaging findings, presence of symptoms, surgical procedure performed, and ovarian torsion occurrence. Patient age at diagnosis was similar between groups (SM: 8.8 vs EM: 8.0, P =.55). At presentation, 36 patients (82%) underwent SM and 8 (18%) underwent EM. There was a significant difference in cyst size between groups (SM: 8.9 cm vs EM: 3.6 cm, P =.004). Of SM patients, 30% underwent oophorectomy vs cystectomy, with a significant difference in ODC size between procedures (11.8 cm vs 7.7 cm, P =.016). Of EM patients, 75% had at least one and 60% had three follow-up ultrasounds, with average follow-up timeframes of 3.7 and 27 months respectively. Average yearly ODC growth rate for the latter group was 0.8 cm. The average yearly growth rate of ODCs in premenarchal patients within our institution was slower than in older cohorts, and both age and cyst size played significant roles in determining surgical procedure. Continued study on EM in premenarchal ODCs will help define parameters for recommending SM vs EM in this population. [ABSTRACT FROM AUTHOR]