The event determines who will lead the Party. Those people will go on to lead the 1.3 billion people of China - most of whom don't get a say - and helm the world's second largest economy.
The 19th congress will begin on 18 October and while significant leadership changes are expected current Party leader and Chinese President Xi Jinping is widely expected to stay in the top job....
...The party has 2,300 delegates - although only 2,287 have been elected to attend, with reports suggesting the remaining 13 delegates were disqualified because of "improper behaviour".
Behind closed doors, those CPC delegates will elect the powerful Central Committee, which has about 200 members.
This committee in turn elects the Politburo and from that, the Politburo Standing Committee is chosen.
Those are China's real decision-making bodies. The Politburo currently has 24 members, while the Standing Committee has seven, although these numbers have varied over the years.
While there is a vote, in reality many of these people have already been handpicked by the current leadership, and the committee just approves their edict.
The Central Committee also elects the Party's top leader - the general secretary - who becomes the country's president. That is, and will most likely continue to be, Xi Jinping.
