In general, infection control professionals apply multimodal strategies to prevent the occurrence of adverse events, including outbreaks in the healthcare setting. However, when an outbreak occurs, they require intensive and rapid expenditure of human and material resources to contain them. In fact, if an outbreak is not quickly controlled, the risk of significant morbidity, mortality, professional burnout and costs increase, and the healthcare setting credibility may be seriously affected. In some cases, outbreaks can originate epidemic or even pandemic scenarios. For these reasons the early identification, study and control of outbreaks is of high importance. This chapter covers basic epidemiologic definitions applied to outbreak identification and management. Oubreak investigation is divided in several steps, which aim the implementation of measures to control and prevent its recurrence.