This study evaluated the prognosis of functional hypothalamic amenorrhea (FHA) and the predictive factors of recovery, through a long-term follow-up. Ninety-three women affected by FHA underwent a follow-up for an average period of 8.1 yr (range 7-9 yr). At the end of the follow-up, 65 (70.7%) patients recovered. Statistical analysis showed that there was no association between recovery and anamnestic causes of FHA or with the echographic ovarian morphology but identified the predictive factors of recovery as the basal body mass index (BMI), the basal cortisol, and androstenedione plasma levels. A higher basal BMI and A, and lower cortisol values are positive prognostic factors for the recovery. Also the BMI, acquired during the follow-up, is important for FHA resolution: in fact, in recovered women the BMI increased or remained stable, whereas in nonrecovered women it decreased or remained stable. At the end of the follow-up, 52 (74.3%) patients treated with hormone replacement therapy and 8 (80%) with no therapy recovered, but only 5 (41.7%) with oral contraceptive pills recovered.