Mr Mugabe was presented with a cake said to weigh 89kg (196lb), and gold coins were minted to mark the occasion.
The celebrations cost about $600,000 (£400,000), reports say.
In his speech, Mr Mugabe – who has ruled since 1980 – denied claims that he was trying to intimidate political rivals ahead of a new election.
Mr Mugabe will be contesting the election later this year, hoping to secure another five-year term in office.
‘Down with imperialism’
The day before the celebrations in Bindura, residents were given an hour off work to clean the town’s streets.
Wearing an elegant suit and a red cap with his year of birth, Mr Mugabe waved to the crowds, flanked by his wife and two children.
He later cut the birthday cake and released 89 balloons into the sky.
In his speech, Mr Mugabe urged his supporters to go “forward with winning elections, down with imperialism”.