Retained surgical foreign objects (RFO) include surgical sponges, instruments, tools or devices that are left behind following a surgical procedure unintentionally. It can cause serious morbidity as well as even mortality. It is frequently misdiagnosed. It should be considered in the differential diagnosis of any postoperative case with unresolved or unusual problems. Risk factors for RFOs include emergency procedures, unplanned change in operation, and body mass index and are clarified as being more frequent approximately 1 in 700 emergent cases. Although human errors cannot be completely prevented, medical training and consistency to rules seem to reduce the incidence to a minimum. It is a legal issue and potentially dangerous medical error. The definition, types, incidence, risk factors, complications and prevention strategies from RFOs are reviewed, from the comprehensive series until the year 2014.