A 12-month-old boy developed a mild hemolytic uremic syndrome with no acute diarrheal prodrome. The typical clinical, hematological, and serological features of infectious mononucleosis were also noted. The clinical course of both hemolytic uremic syndrome and infectious mononucleosis was uneventful. A review of the literature disclosed that hemolytic uremic syndrome has been noted in two adolescents with infectious mononucleosis.