Prader-Willi syndrome (PWS) is a neurodevelopmental disorder characterized by an insatiable appetite, dysmorphic features, cognitive and behavioral difficulties, and hypogonadism. The heterogeneous reproductive hormone profiles indicate that some PWS women may have symptoms of hypoestrogenism, while others may potentially be fertile. We describe our experience in the assessment and treatment of hypogonadism in adolescents and adult females with PWS. The study population consisted of 20 PWS females, age ≥16 years (27.3 ± 7.9 years), followed in our clinic (12 deletion, 7 uniparental disomy, 1 imprinting-center defect). General physical examination, pubertal assessment, body mass index (BMI), gynecological examination, ultrasonography, bone densitometry, and hormonal profiles [FSH, LH, inhibin B, estradiol, prolactin, and TSH] were performed. The relevant assessed factors were: FSH and inhibin B, menstrual cycles (oligo/amenorrhea or irregular bleeding), ultrasound findings (endometrial thickness, uterine/ovarian abnormalities), BMI, bone densitometry, and patient/caregivers attitude. We classified seven women with inhibin B >20 ng/ml as potentially fertile. Following the assessment of the above factors, we recommended the individual-specific treatment; contraceptive pills, intra-uterine device, estrogen/progesterone replacement, and cyclic progesterone, in 3, 1, 4, and 1 patients, respectively. Four patients did not follow our recommendations due to poor compliance or family refusal. We recommended contraception pills for one 26-year-old woman with inhibin B and FSH levels 53 ng/ml and 6.4 IU/L; however, she refused treatment, conceived spontaneously and had an abortion. Guidelines for hormonal replacement therapy in PWS need to be tailored individually depending on physical development, hormonal profiles, bone density, and emotional and social needs of each PWS adolescent and adult. © 2013 Wiley Periodicals, Inc.