Cyclosporiasis is a food- and water-borne infection that affects healthy and immunocompromised individuals. Awareness of the disease has increased, and outbreaks continue to be reported among vulnerable hosts and now among local residents in endemic areas. Advances in molecular techniques have improved identification of infection, but detecting food and water contamination remains difficult. Further understanding of the biology, pathogenesis, and control of infection and transmission has been hindered by the difficulty of propagating the organism, lack of reliable oocyst viability and infectivity assays, and inability to experimentally infect animals and human volunteers. This article provides a general review and presents recent insights into the organism and disease.