Human infection has been reported with groups A, B, and C rotaviruses (RVs). Of these, Group A RVs are the most important, being a major cause of severe gastroenteritis (GE). Each year, Group A RVs are estimated to cause approx 870,000 deaths worldwide in children less than 5 years (yr) of age, mostly in developing countries (1). This chapter will describe the epidemiological features of Group A RV infections, and will critically review the current surveillance strategies used to define the burden of disease.