Titus Naikuni, the Kenya Airways group managing director, said that the 737 was carrying 106 passengers and nine crew.
"The last message from the aircraft was received by the control tower in Douala immediately after take-off," Kenya Airways said on its website.
"Flight 507 was coming from Abidjan via Douala. The aircraft unfortunately has not arrived," Naikuni told a news conference in Nairobi.
"We have no details at the moment as to what happened to our aircraft."
The airline said it opened a crisis management centre near the airport and had no further details.