We describe an acute febrile respiratory infection outbreak in a military unit in Trujillo, Peru. Cases were identified using the influenza like illness (ILI) definition of the Ministry of Health. Nasal swab samples used for a rapid influenza test (RIT) and pharyngeal swab samples for viral isolation were taken. For influenza A, genotyping of a partial sequence of the hemagglutinin region was performed. The rate attack was 82.9%. Fifty-nine cases appeared between April 1 and 8, 2008; 58 came from the military unit (MU) #1 and one from the MU #2. The RIT identified 40 cases of influenza A and 43 cases were confirmed through cell culture. Isolations were genetically similar to the A H1N1 Brisbane strain. Early detection of outbreaks in confined locations such as military bases permits immediate action in preventing disease propagation.