The differential diagnosis of infectious uveitis is broad and an essential step in any initial work-up. Underlying organisms include all types of infectious agents. The more common infectious causes of uveitis include viral causes, toxoplasmosis, syphilis, tuberculosis and endogenous endophthalmitis that will be covered in this course. Based on clinical features further diagnostic tools will be discussed and critically reviewed. In particular newer evolving techniques in the investigations will be included, e.g. intraocular fluid evaluation for polymerase chain testing for the genome and antibody testing against the causative organisms.