In 1992, a new type of influenza virus appeared in Southeast Asia. This new strain has caused to date, more than 120 cases and over 60 deaths in Cambodia,Vietnam, Indonesia and Thailand. This situation is seen by the experts as the possible genesis of a new influenza pandemic with the corresponding negative effects on the health of the population, international commerce and world economy. In order to face the coming challenge, the World Health Organization (WHO) has asked member countries to develop national preparedness and response plans for an influenza pandemic. Within the framework of the National Committee for Health Security, Mexico has developed a National Preparedness and Response Plan for an Influenza Pandemic with the aim of protecting the health of the population with timely and effective measures. The Plan is based on a risk scale and five lines of action: Coordination, Epidemiological Surveillance, Medical Care, Risk Communication and Strategic Stockpile. It is currently impossible to predict when the next pandemic will start or what will be its impact. Nevertheless, it is fundamental that national and regional health authorities establish measures for protecting the health of the population in case this emergency occurs.