The proband was of Arabic descent and evaluated for intractable diarrhea and poor growth. Molecular testing identified a nonsense mutation in the sucrase-isomaltase (SI) gene consistent with a diagnosis of sucrase-isomaltase deficiency (CSID). Appropriate treatment led to resolution of symptoms and improved growth. This case represents the first report of CSID with molecular confirmation in a patient without known European ancestry and demonstrates the importance of genetic testing for congenital diarrheal disorders.