Communist Party of Indonesia ( Indonesian : '' Partai Komunis Indonesia '' , PKI ) was a communist party in Indonesia that existed throughout the mid-20th century . It was the largest non-ruling communist party in the world prior to being eradicated in 1965 and banned in the following year . The party counted 2 million members in the 1955 elections with 16 percent of the national vote and close to 30 percent of the votes in East Java . During most of the period immediately following independence until the eradication of the PKI in 1965 , the PKI was a legal party operating openly in Indonesia ’s political system
eradicated in 1965
Indonesian mass killings of 1965–66
Communist Party of Indonesia