Intraocular inflammation, or uveitis, incorporates a diverse group of infectious and immune-mediated disorders. In addition, some conditions masquerade as uveitis. However, classifying uveitis according to anatomic location in adult and pediatric populations, and appreciating the effect of immune status and regional differences, refines the list of potential causes. In this way, a select few investigations can be performed, rather than a nondirected battery of tests.