In Peru, diphtheria infection was eradicated in the last two decades. However, recently, diphtheria pharyngeal infection was confirmed and reported in a 5-year-old boy (index case). We report two more cases of this out-break (in the index case parents) with confirmed diphtheria infection and tox gene identified by molecular as-say, who were in close contact with the index case and never presented any symptoms. Both parents had a con-gestive pharynx with erythematous plaques at the back of it. In adults, diphtheria infection can be oligosympto-matic or mimic viral pharyngitis, which could lead to misdiagnosis and, furthermore, an increased risk of transmission in regions with lower immunization rates.