V.H., a 68-year-old right-handed woman, presented with a progressive deterioration in her ability to recognize faces of familiar people, including friends and relatives. Neuropsychological testing on two occasions separated by 9 months indicated no deterioration in general intellectual ability from estimates of her pre-morbid IQ (in the high average range), and little or no change in memory, language, perceptual or executive functioning. She is severely impaired on tests of face recognition and has shown some deterioration between testing occasions. In contrast, face perception skills, including emotional expression analysis, appear to be intact. Her knowledge of people from names was originally much better than from faces, but clearly declined on follow-up. This progression is discussed in the context of contemporary models of face processing: we suggest that her prosopagnosic deficit began as a modality-specific disorder which has progressed to a cross-modality loss of person-based semantic knowledge. In addition, she shows a striking dissociation between her ability to recognize faces and unique exemplars from other categories, such as buildings and flowers, which confirms the hypothesis that face processing is indeed special. Scanning by SPECT and MRI revealed selective hypoperfusion and atrophy, respectively, of the anterior part of the right temporal lobe. In recent years there have been a number of descriptions of progressive fluent aphasia resulting from atrophy of the left temporal lobe. This case appears to represent a corresponding degenerative process affecting the right temporal lobe.