After acute infectious gastroenteritis, up to thirty percent of patients present prolonged gastrointestinal symptoms and a part of those affected patients can have the diagnostic criteria for postinfectious irritable bowel syndrome. The main diagnosis of a patient with postinfectious irritable bowel syndrome was till this summer, clinically based on Roma III criteria. The Rome IV criteria brought some changes that involve also the post infectious irritable bowel syndrome, recognizing further the postinfectious IBS as a specific entity according to the multidimensional clinical chronic mucosal inflammation triggered by enteric infection, may underlie persistent bowel symptoms in patients who develop postinfectious irritable bowel syndrome.