Background: Precocious puberty, as early physical development and low final height might lead to psychosocial problems.Objective: To evaluate etiology and clinical feature of precocious puberty in a cohort of Iranian children.Materials and Methods: In this case-series study, 44 girls and 8 boys with precocious puberty referred to Endocrine Reserch Centre (Firouzgar), Institute of Endocrinology and Metabolism (Hemmat Campus), were examined in a 10 years period of time.Results: Mean age of girls and boys was 7.43±1.4 years and 5.8±2.1 years respectively. Most of the patients fell within the age category of 7-7.9 years old (40.9% for girls and 50% for boys). Patients, concerning etiology of precocious puberty were classified in three categories: 42.6% of patients had central precocious puberty (CPP), including idiopathic CPP (87.5%) and neurogenic CPP (12.5%).23.3% of patients had peripheral precocious puberty (PPP), including congenital adrenal hyperplasia (CAH) (42.8%), ovarian cysts (28.4%), McCune-Albright syndrome (14.2%) and adrenal carcinoma (14.2%).34.1% of girls and 25% of boys had normal variant puberty including premature thelarche (57%), premature adrenarche (38%) as well as premature menarche (4.7%l).Conclusion: The most common etiology of precocious puberty in girls was idiopathic central precocious puberty and premature thelarche, while in boys they were neurogenic central precocious puberty and CAH. Therefore precocious puberty in girls is usually benign. In boys, CNS anomalies should first be considered in the differential diagnosis of CPP. Therefore brain Magnetic Resonance Imaging (MRI) is mandatory in all cases.