This report describes 4 narcolepsy cases that were developed after Influenza A/H1N1 infection or vaccination. The durations from Influenza A/H1N1 infection or vaccination to the symptom onset were 10 days, 2 weeks, 3 months, 6 months respectively. Among the four, two were teenagers or younger. One of them developed symptoms after Influenza A/H1N1 infection while three of them developed after vaccination. All went through polysomnography followed by multiple sleep latency tests for accurate diagnosis. All suffered from cataplexy. However, one of them presented with negative results in the human leukocyte antigen DQB1*0602 study. These cases suggest a possibility an association between H1N1/Influenza A virus and narcolepsy development via immune mechanism.