Despite the advent of rotavirus vaccination, viral gastroenteritis remains a significant clinical and diagnostic problem. Rotavirus has been succeeded by noroviruses as the most prevalent cause of viral gastroenteritis but a significant portion of cases of gastroenteritis remain undiagnosed. This paper will review the causes of viral gastroenteritis and their prevalence in differing age groups and, 40 years after the identification of rotavirus will review recent information on the pathogenesis of rotavirus gastroenteritis.