Cereal grains contribute more than half of the global daily calorie intake. However, cereal crops are prone to attack by plant pathogens that cause devastating losses estimated in the billions of dollars, threatening global food and economic security. One of the diseases of small grain cereals that is of major economic importance is Fusarium head blight (FHB). It affects all small grain cereals, but major economic losses occur in wheat and barley production. FHB is caused mainly by Fusarium species in the Fusarium graminearum species complex, of which F. graminearum is the predominant causal agent. Understanding the epidemiology of F. graminearum is critical to the development of effective and sustainable FHB management strategies that will reduce or prevent losses. This chapter reviews recent advances in the epidemiology of F. graminearum in cereal crops.