On October 29, 2000, the Regional Commission for the Certification of Poliomyelitis Eradication certified that the Western Pacific Region (WPR) of the World Health Organization (WHO) is free of indigenous wild poliovirus transmission. The last known case of indigenous poliovirus transmission occurred in Cambodia in March 1997 in a 15-month-old girl. WPR is the second of the six WHO regions to be certified as poliomyelitis-free; the first was the Region of the Americas in 1994. WPR comprises 37 countries and territories (Figure 1) with an estimated 1.6 billion persons (27% of the world's population).