Since November 2003, the epidemic intelligence team at the French Institut de Veille Sanitaire has been gathering data on influenza A(H5N1) circulation in poultry and on human cases worldwide. As Indonesia notifies the world's 500th case to the World Health Organization, we discuss the epidemiological situation and trends of A(H5N1) influenza. Although the overall number of cases reported worldwide has decreased, influenza A(H5N1) continues to circulate intensely in some countries and more cases are to be expected, especially in Egypt and Indonesia. (R.A.)