Reproduction is affected by various factors, including among others, nutrition, exposure to infections, and hormonal milieu of the individual. Endocrine disorders have a profound impact on reproduction and in women, polycystic ovarian syndrome (PCOS) is the most common endocrine syndromic disorder affecting reproduction. This chapter discusses abnormalities of the hypothalamus, pituitary, adrenals, and thyroid, and their effect on reproduction. For long known as the “master gland”, the pituitary was thought to regulate almost all essential functions of the body, including growth, response to stress, functioning of thyroid, and reproduction to name a few. The adrenal gland embryologically and anatomically is divided into the cortex and medulla, with the latter being a part of the sympathetic nervous system, producing epinephrine. The more important adrenal cortex has the aldosterone-secreting zona glomerulosa controlled by the renin-angiotensin-aldosterone system (RAAS), the cortisolsecreting zona fasciculata and the dehydroepiandro-sterone (DHEAS)-secreting zona reticularis, both of which are regulated by the adrenocorticotropic hormone (ACTH).