Ischemic optic neuropathies (IONs) are one of the common causes of visual loss presenting in neurology/ophthalmology or internal medicine clinics. Because of the association of ION with systemic vascular risk factors like diabetes, hypertension and dyslipidemia, it becomes increasingly important to suspect and clinically diagnose these patients. The sudden onset, rapid progression, severe visual loss and altitudinal field defects may provide clues toward the diagnosis. The presence of pale disc edema with flame-shaped hemorrhages on ophthalmoscopic examination may further provide evidence of vascular involvement. While it is important to recognize the difference between ischemic and inflammatory optic neuropathies, it is also important to differentiate between arteritic and non-arteritic varieties of ION. We will discuss about clinical clues for diagnosis of ION and how to differentiate ION from other causes in this chapter. This chapter also provides a case-based scenario of a step-by-step approach to be followed once a patient suspected to be having ION presents.