“The endocrinal system has been aptly compared to an orchestra,” is how the Chapter gets off the ground. The hypothalamus acts as a “master” or “director” whereas the pituitary gland is the “conductor” in this endocrine orchestra. The conductor is subservient to not only the hypothalamus but is also controlled by the feedback from the glands it stimulates. At no other span of life the endocrines and their metabolic and biochemical effects are more vital than in infancy and childhood. This is more or so since stimulation of physical as also sexual growth is a unique feature of this age. Henceforth, the text moves on to discuss hypothalamus and its disorders with special reference to diabetes insipidus, pituitary and its disorders, growth hormone deficiency (GHD), thyroid and its disorders, parathyroid and its disorders, adrenal and its disorders, and gonads and their deficiency. Congenital hypothyroidism is particularly described in considerable details with emphasis on its early diagnosis and therapy with levothyroxine. If adequate replacement therapy is initiated in the first 6 months of life, outlook for physical growth is fairly gratifying. About half of them can also accomplish an IQ of 90 or even more. Finally there are good updates on diabetes mellitus with special reference to diabetic ketoacidosis (DKA) and obesity.