Red eyes are commonly encountered in optometric practice and it is imperative that the eyecare practitioner is able to formulate an appropriate differential diagnosis in order to manage patients effectively and expeditiously. The emphasis of this lecture is to highlight the importance of the ophthalmic history and examination techniques employed in establishing such a differential diagnosis and to provide an overview of those conditions likely to present to either ophthalmic, dispensing or contact lens practitioners. Finally, principles of management with particular reference to referral criteria will be discussed.