A huge majority of Uganda's voters - 92.5% - has supported restoring multi-party politics.
The vote is expected to favour of a return to multi-party politics
However, the turnout from Thursday's referendum was rather low with about 47% of people voting.
President Yoweri Museveni called for a big turnout, while the opposition called for a boycott, dismissing it as a waste of time and money.
A BBC correspondent says there is now no doubt that political parties will be able to campaign for next year's polls.
Political parties have been severely restricted in Uganda for the last two decades under the "Movement" system.
In a similar plebiscite five years ago, Ugandans opposed a return to multi-party politics, which Mr Museveni then argued would divide people along ethnic lines.
BBC correspondent Will Ross in Kampala says in one polling station there less than a third of registered voters turned out.
He says many people questioned the purpose of the referendum as the Ugandan government and the political parties had all said they wanted a return to multi-party politics.
For years Mr Museveni opposed political parties, but internal and international pressure for more democracy changed his position.
Inadequate civic education prior to the vote left many confused about the process which cost around $13m (£7.4m), says our correspondent.
However, donors have recently reduced aid to Uganda because of moves to drop a constitutional limit on presidential terms.
Mr Museveni is nearing the end of his second term but now looks set to be allowed to stand in next year's polls.
Correspondents say this was a curious poll, with Mr Museveni, who has championed the idea of non-party politics since he came to power 19 years ago, travelling the country seeking support for a return to multi-party politics.
The opposition, which says political pluralism has already been established, is demanding a boycott.