This is a report of a case of human nasal myiasis caused by third instar larvae of the sheep nasal bot fly, Oestrus ovis. Female flies rarely deposit first instar larvae in the eye, nostrils, and external auditory canal of humans, where they usually survive only a few days without further development. One human infestation by third instar larvae of O. ovis has been recorded in an patient infected with human immunodeficiency virus (HIV) in the United Kingdom. Our report describes a new case of nasal myiasis caused by the third instar larvae of the sheep bot fly in a patient without HIV or signs of any other disease.