A pig-borne virus causing viral encephalitis amongst human beings in Malaysia was detected in 1997 by the Ministry of Health. Initially, the disease was considered to be Japanese encephalitis. Subsequently, it was thought to be a Hendra-like viral encephalitis, but on 10th April, 1999 the Minister of Health announced this mysterious and deadly virus to be a new virus named Nipah virus. The virus was characterized at CDC, Atlanta, Georgia. The gene sequencing of the enveloped virus revealed that one of the genes had 21% difference in the nucleotide sequence with about 8% difference in the amino acid sequence from Hendra virus isolated from horses in Australia in 1994. The virus was named after the village Nipah. In all, the Ministry of Health declared 101 human casualties, and 900,000 pigs were culled by April, 1999. The worst affected area in Malaysia was Negri Sembilan. The symptoms, incubation period in human being and pigs, animal to human transmission, threat of disease to other livestock, and control program adopted in Malaysia is described.