Mohammed Dewji, who has been described as Africa's youngest billionaire, was abducted on Thursday morning by gunmen in Tanzania's economic capital Dar es Salaam, police said.
The 40-year-old was seized by two masked men as he entered the gym of a luxury hotel in the city.
The two kidnappers fired a gun and then they opened the gate, Dar es Salaam Regional Commissioner Paul Makonda said, adding that the two were believed to be foreign nationals.
Makonda said police have tightened security at all border points and airports to ensure that the two white men who were seen on surveillance video did not leave the East African nation.
Police have already made some arrests.
A former lawmaker, Dewji is the owner and president of the multi-billion dollar revenue Mohammed Enterprises Tanzania Ltd (METL Group).
Forbes business magazine puts Dewji's wealth at $1.5 billion (€1.3 billion) and describes him as Africa's youngest billionaire.
Dewji is also the main shareholder in Tanzania's Simba FC football club.
ap/kms (AP, AFP, Reuters)