Purpose To evaluate the capacity of random antral follicle count (AFC), i.e., AFC recorded at any time during the menstrual cycle, to predict the number of retrieved mature oocytes in women with malignancies undergoing random start ovarian hyperstimulation Methods A consecutive series of 72 women with malignancies who underwent ovarian hyperstimulation aimed at egg freezing between July 2014 and December 2016 was retrospectively reviewed. A standardized random start protocol was used for all women. AFC and serum AMH were systematically assessed prior to initiating ovarian hyperstimulation. The main outcome was the retrieval of ≥ 10 mature oocytes. The accuracy of random AFC was tested with the c-statistics (area under the ROC curve). Results For the whole cohort, the c-statistics for the prediction of ≥ 10 mature oocytes using AFC and serum AMH were similar. Specifically, the areas under the curve were 0.76 (95%CI 0.66-0.87) and 0.82 (95%CI 0.72-0.92), respectively (p = ns). Moreover, when considering the subgroup of women recruited after day 5 of the cycle (proper random start, n = 52), the areas under the curve did not also differ. Specifically, they resulted in 0.77 (95%CI 0.64-0.89) and 0.83 (95%CI 0.72-0.95), respectively (p = ns). Conclusions AFC collected at any time during the menstrual cycle can provide valuable information for the counseling of women with malignancies scheduled for oocyte cryopreservation. Its reliability appears to be non-inferior to that of serum AMH.