Premature ovarian failure (POF) is a disorder associated with female infertility, and it affects approximately 1% of women under the age of 40 yr. Resumption of ovarian activity and spontaneous pregnancies are described in patients with premature ovarian failure (POF), but there is a lack of data concerning the prevalence of and predictive factors for these causes. Objective: The aim of the study was to determine both the prevalence of and predictive factors for spontaneous resumption of ovarian function in POF patients. Methods: A mixed retrospective and prospective study was performed at center of endocrinology of Uzbekistan. Patients: A total of 240 consecutive POF patients were followed from 2010 to 2017 in our center. Spontaneous POF was defined by at least 4 months of amenorrhea, two FSH readings above 30 mIU/ml at least 1 month apart, and a karyotype excluding Turner's syndrome and gonadal dysgenesis. None of the patients had a history of chemotherapy and/or pelvic radiotherapy. Main Outcomes Measures: The cumulative incidence of resumption of ovarian function was determined, and predictive factors were identified by univariate and multivariate analysis. Results: Of 240 patients with idiopathic POF, in 56 (23.3%) patients presented features indicating resumption of ovarian function, and in 39 cases (75%) within 1 year of diagnosis. 17 spontaneous pregnancies were observed at 13 patients. From them there were 13 births, 4miscarriages. At 45 patients presented a decrease in FSH level above the normal range. Multivariate analysis (Cox model) showed that a familial history of POF, secondary amenorrhea, presence of follicles at ultrasound, and inhibin B and estradiol levels were significantly predictive of resumption of ovarian function (p < 0.01), whereas association with an autoimmune disease, anti-Mullerian hormone level, and genetic abnormalities did not appear predictive. We created a predictive score for resumption of ovarian function comprising age at diagnosis, presence of follicles at ultrasound, and inhibin B level. Conclusion: In conclusion, spontaneous resumption of ovarian function is not a rare phenomenon in POF patients. Our studies led to the identification of predictive factors for such resumption. This study may help to select POF patients with the greatest likelihood of intermittent ovarian function.