We describe a case series of group A Streptococcus (GAS) necrotizing fasciitis occurring over a 10-week period in military recruits undergoing intense physical training. These cases highlight that GAS may cause life-threatening infections in addition to mild diseases such as pharyngitis. This series suggests that the incidence of severe GAS infections may be increasing in certain populations and it emphasizes the importance of considering prophylactic measures against GAS in high-risk populations.