Influenza A (H1N1) is a new human infection that causing a pandemic in year 2009. In Malaysia, the total number of death was 79 in April 2010. The Minister of Health Malaysia had announced that there were possibilities that the virus could generate a deadlier second wave and might lead to a national health emergency. This book illustrates methods used to validate the knowledge, attitude and practice of influenza A (H1N1) questionnaires (KAPH1N1Q). Cronbach's alpha and exploratory factor analysis were used to assess the reliability and construct validity of the questionnaires. The KAPH1N1Q had satisfactory reliability and validity to assess the knowledge, attitude and practice on influenza A (H1N1).