The understanding of ocular physiopathology and pharmacokinetic and pharmacodynamic parameters of ophthalmic drugs has increased and resulted in the development of new drugs and drug delivery systems for the human eye. Veterinary ocular pharmacology is a new field of study and although pertinent information on the effects of ocular drugs and their proper use in small and large animal patients has increased, the veterinary-labeled ophthalmic drugs presently available in most countries consist primarily of topical antibiotics and antibiotic- corticosteroid combinations and there is a limited number of other drug categories for topical use. This chapter provides some comparative anatomical and physiological features of the eye in the species most frequently encountered in veterinary practice and presents their essential ocular diseases and describes the most appropriate medications for such diseases. It also discusses the application of currently available ocular systems to veterinary ophthalmology and recent developments in the field of drug delivery to the human eye and their possible application to veterinary ophthalmology.