Tim Dixon and Waheed Raja will take up their respective seats after a great result for the Lib Dems.
Liberal Democrat candidate Waheed Raja will take the Central and Walton seat, with 551 votes, after Edwards Sims resignation earlier this year.
Tim Dixon, also from the Liberal Democrats has also won Central Aylesbury Town Council seat with 307 votes.
A statement from AVDC said: "We can now confirm the total ballot papers and turnout for today's District and Town Council by-elections.
"The total turnout was 1,355, equating to 27.85%."
The vote breakdown for the Central and Walton seat was as follows:
Liberal Democrat: 40.9% (+18.1)
Conservative: 31.5% (-1.1)
Labour: 19.8% (+0.9)
Green: 4.5% (-4.0)
Independent: 3.3% (+3.3)
No candidate from UKIP this year, which means their vote was down (-17.2)
The vote breakdown for the Central Aylesbury Town Council Ward were:
Tim Dixon, Liberal Democrat: 307 votes
Liz Hind, Labour: 215 votes
Kyle Arron Paul Michael: 40 votes
Lou Redding, Conservative: 201 votes
Total ballot papers counted: 767