SUMMARY: The researchers describe the case of a earlier healthy 3-year-old boy, who developed immune thrombocytopenic purpura (ITP) 26 days after immunization with the second dose of seasonal influenza vaccine. He recovered quickly and uneventfully within 2 days after receiving a single dose of intravenous immunoglobulin. Review of the medical literature showed that symptomatic thrombocytopenia occurs in a substantial number of children and adults who require hospitalization for complicated natural influenza infection, particularly avian influenza. In contrast, it is exceptionally rare after influenza immunization, as only few case reports describe such an association in adults but not in children. As the risk of thrombocytopenia after natural influenza seems to be much higher than after immunization, annual influenza vaccination is advised for patients with personal history of ITP who at risk of influenza-related complications owing to underlying medical problems.