Microbial keratitis is an infectious inflammation of the cornea which, if not rapidly diagnosed, may lead to loss of vision. The investigative procedures are demanding for the ophthalmologist and confirmative diagnosis a formidable challenge to the microbiologist. Most, if not all, bacteria can cause keratitis. To establish a diagnosis culture is essential, since it is not possible clinically to distinguish between one type of infective keratitis and another. A relatively new and worrying problem is acanthamoebic keratitis, which is significantly associated with contact lens wear. It is increasing in incidence as lens wear becomes more popular. Although Acanthamoebae are easily isolated, many laboratories are not familiar with laboratory methods for diagnosis.