Rickets is a condition of inadequate mineralization of osteoid and cartilage at the growing ends of bones in children. In this brief review, we first explained the regulation of serum Ca and P concentrations to understand Rickets. Second, four types of sub-division of Rickets are presented ; 1) Vitamin D dysfunction-related, 2) Phosphate deficiency-related, 3) both 1) and 2) -related, 4) others. Finally, as most common entities, diagnosis and treatment in vitamin D deficiency and inherited hypophosphatemic Rickets/Osteomalacia are described. Over production of Klotho and inactivating mutations of FAM20c are explained as recent etiologies of non-hypercaluciuric inherited hypophosphatemic Rickets/Osteomalacia.