Background: Influenza A has a potential to become a pandemic, in the early stages is difficult to differentiate influenza to influenza-like illnesses. Therefore, the dominant clinical symptoms are the important keys to predict influenza A infection in patients with influenza-like illnesses (ILI). The aim of this study is to identify additional dominant symptoms associated to influenza A in Indonesia.Methods: The eligible subjects of this study were outpatient who had ILI symptom, i.e. who had fever (38o or more) and coughing in purposive selected 20 Health Centers in 19 provinces of Indonesia during year 2009. Paramedics and medical staff identified the ILI cases and collected specimens. Laboratory tests for RT-PCR were performed at the National Influenza Center in Jakarta.Results: Of 2728 specimens, 1802 had complete data for this analysis, and 23.1% (416 subjects) diagnosed positive influenza A. Those who had than did not have runny nose symptom had 3.6-fold risk of influenza A [adjusted relative risk (RRa) = 3.59; 95% confidence interval (CI) = 1.34-9.63). In term of sore throat, those who had than did not have it had 54% more risk of influenza A (RRa = 1.54; 95% CI = 0.95-2.58; P = 0.082). Furthermore, those who ever had than did not have fever for the last two days had 42% more risk of influenza A (RRa = 1.42; 95% CI = 0.97-2.07; 0,069).Conclusion: In addition to fever and coughing, runny nose, sore throat, and ever had fever are dominantly associated with influenza A. (Health Science Indones 2011;2:96-100)