Since his international debut in 2004, Guerrero has earned over 100 caps for Peru and is the nation's all-time top goalscorer with 38 goals, representing them at five Copa América and one FIFA World Cup tournaments. He helped them to third place in the 2011 and 2015 editions, and to runners-up in 2019, finishing as top scorer in all three of these tournaments. He is also the current all-time top scorer in the history of the Copa América among active players. He was one of 59 nominees for the 2015 FIFA Ballon d'Or, the first Peruvian to receive that recognition. He's also the oldest Peruvian player to appear in a World Cup, at the age of 34 and 177 days.