President Robert Mugabe, in power since independence, was due to deliver the keynote address at Harare's Chinese-built 60,000-seat National Sports Stadium.
Hosting an independence party for thousands of children on Saturday, Mugabe urged youths to defend the country's sovereignty from Western "interference."
"There are some people trying to interfere with our freedom, the British, the Americans and all those who support them."
"We are a free people and we shall not brook any interference. We can organise ourselves in defence of this country should there be interference from these people," Mugabe said.
A few armed police patrolled the centre of the capital as the official ceremonies got under way.
The state-run Sunday Mail carried a 10-page special supplement on the independence anniversary with features on various topics including land, economy, media and political and race relations.
"We are a free people and we shall not brook any interference. We can organise ourselves in defence of this country should there be interference from these people"
Zimbabwe is celebrating its independence this year with inflation having almost trebled from 228% the same time last year to 600%.
At least 80% of the country's 11.6 million people live well below the poverty line, and unemployment levels are unofficially pegged around 70%.