Background. Little is known about the community psychological and behavioral responses to influenza pandemics. Methods. Using random digit dialing, we sampled 12,965 Hong Kong residents in 13 cross-sectional telephone surveys between April and November 2009, covering the entire first wave of the 2009 influenza A(H1N1) pandemic. We examined trends in anxiety, risk perception, knowledge on modes of transmission, and preventive behaviors. Results. Respondents reported low anxiety levels throughout the epidemic. Perceived susceptibility to infection and perceived severity of H1N1 were initially high but declined early in the epidemic and remained stable thereafter. As the epidemic grew, knowledge on modes of transmission did not improve, the adoption of hygiene measures and use of face masks did not change, and social distancing declined. Greater anxiety was associated with lower reported use of hygiene measures but greater social distancing. Knowledge that H1N1 could be spread by indirect contact was associated with greater use of hygiene measures and social distancing. Conclusions. The lack of substantial change in preventive measures or knowledge about the modes of H1N1 transmission in the general population suggests that community mitigation measures played little role in mitigating the impact of the first wave of 2009 influenza A(H1N1) pandemic in Hong Kong.