Objective: To evaluate potential associations between concentrations of antimüllerian hormone (AMH) and T as well as the LH/FSH ratio and the unbiased precise ovarian volume obtained after unilateral ovariectomy. Design: Cohort study. Setting: University hospital. Patient(s): A total of 765 patients having one ovary surgically removed for fertility preservation. Inclusion criteria were age >15 years and ovarian volume <25 mL; 386 women had one or more hormone parameter (AMH, LH, FSH, or total T) determined before oophorectomy. Intervention(s): None. Main Outcome Measure(s): A precise weight of the ovary was equated with ovarian volume. Associations between ovarian volume and AMH, the LH/FSH ratio, T concentrations, and body mass index (BMI) were evaluated. Patient characteristics in relation to ovarian volume cutoff values between 8 and 12 mL were also examined. Result(s): Ovarian volume was significantly positively associated with concentrations of AMH, the LH/FSH ratio, and T. Ovarian volume, concentrations of AMH and LH, and the LH/FSH ratio were significantly augmented in women having ovarian volumes above a threshold of 8, 9, and 10 mL compared with those below. Average age, FSH, and T concentrations did not differ between below and above the 10 mL threshold. There was a significant association between BMI and ovarian volume and BMI and T, while other hormone parameters were nonsignificant. Conclusion(s): The precise ovarian volume reflected ovarian activity measured as circulating concentrations of AMH and T as well as the LH/FSH ratio. These significant associations showed continuous progression, and a 10 mL threshold offered no clear difference compared with other volume threshold values.