David Sheffield Bell is an American physician who has done extensive research on the clinical aspects of chronic fatigue syndrome (CFS). He has also conducted evaluations and research in pediatric CFS and written numerous articles about the condition. Bell is retired from a private practice in general medicine in the town of Lyndonville, New York which he had started in 1979. Bell also served as Clinical Associate Professor of Pediatrics at the State University of New York at Buffalo, in Buffalo, New York.