Objective: To define frequency and risk factors of abnormalities in growth, puberty, thyroid function, and bone and carbohydrate metabolisms in children and adolescents with sickle cell disease (SCD). Materials and Methods: Endocrine problems including short stature, puberty and thyroid disorders, and carbohydrate and bone metabolisms in 50 Turkish children and adolescents with SCD were evaluated. Relationships among sex, disease type, blood transfusions, exchange and exacerbation frequency, ferritin levels, and endocrine pathologies were investigated. Results: The mean age of the study group was 13.1±2.9 years. Weights and heights of 12 participants (24%) were below -2 standard deviations and 4 participants (8%) had malnutrition. Mean difference (±standard deviation) between bone and chronological age of patients was -1.73±1.86 years. Fifty percent of patients had at least one endocrine abnormality other than vitamin D deficiency and insufficiency. Hypergonadotropic hypogonadism in 3 patients (6%), hypogonadotropic hypogonadism in 1 female patient (2%), and small testicular volume in respect to age in 3 male patients (8.5%) were seen. Growth hormone deficiency was detected in 1 (2%) female patient, and hypothyroidism was diagnosed in 3 patients (6%; 1 central case, 2 cases of primary hypothyroidism). At vertebral level, 5 patients (11.1%) had osteopenia and 1 patient (2.2%) had osteoporosis, while 5 patients (11.1%) had osteopenia at femur neck level. The most common endocrine abnormality was vitamin D deficiency. 25-Hydroxyvitamin D was deficient in 63.2% and insufficient in 18.4% of patients. Sex, disease type, blood transfusion frequency, exacerbation frequency, and ferritin levels were not related to endocrine pathologies. As the age was increased, standard deviation scores of femur neck bone mineral density was decreased (r =-0.56; p<0.05). Vitamin D was lower in patients whose weights and/or heights were below -2 standard deviations from the mean (p<0.05). Conclusion: Endocrine organ dysfunctions are commonly detected in children and adolescents with SCD, and vitamin D deficiency is the most commonly encountered endocrine disorder. Regular follow- ups of patients for endocrine complications, starting from early ages of patients, and initiation of appropriate treatments will elongate expectancy and quality of life. Conflict of interest:None declared.