Mr Mugabe, 92, was arriving back in the country at the main airport in Harare and appeared jovial as he disembarked.
Flight data had suggested his plane was heading to East Asia but that it instead went to Dubai. Mr Mugabe said he had gone there for a family matter.
In May, Mr Mugabe's wife, Grace, said that he would rule from the grave.
The flight path and other rumours had led some to speculate that Mr Mugabe had suffered a serious health problem and had sought treatment in Dubai or had even succumbed to his illness.
The Southern Daily website had posted an article headlined "Robert Mugabe suffers stroke, Mnangagwa now the new interim President of Zimbabwe".
Emmerson Mnangagwa is the country's vice-president.
But Reuters news agency said that on arriving at Harare Mr Mugabe had told reporters in the local Shona language: "I had gone on a family matter to Dubai concerning one of my children.
"Yes, I was dead, it's true I was dead. I resurrected as I always do. Once I get back to my country I am real."
Mr Mugabe is expected to address a youth meeting later on Saturday.
He has been in power since 1980 and has said he will run again for office in 2018.
The country remains in political and economic turmoil, amid allegations of government corruption.
The capital saw a wave of protests last week, with dozens arrested.
Police on Thursday banned demonstrations in the capital for two weeks.
Mr Mugabe has vowed to crack down on anti-government dissent.
Zimbabwean President Robert Mugabe has poured scorn over the latest rumours of his health, joking that he had died and was resurrected.