Abstract: Bird flu, H5N1, infection is a new emerging infectious viral disease. This H5N1 virus jumped the species barrier and caused severe disease with high mortality in humans in recent years. Most infected patients usually developed progressive pneumonia with acute respiratory distress syndrome and consequently died. The hematologic aberration in bird flu infection is noted. Here, the author performs a summative review to document the impact of bird flu infection on hematologic findings among reported infected patients. The main hematologic manifestation of this infection is lymphopenia with decreased lymphocyte/neutrophil ratio. Anemia can also be observed in this infection. The effects of this infection on platelet are still controversial.