Seven survivors are said to have emerged from the burning wreckage of the plane.
The plane was bringing passengers from the capital Abuja when it overshot the runway during an electrical storm and burst into flames.
The DC-9, owned by the private Sosoliso Airlines, was said to be carrying dozens of school pupils.
The cause of the crash is not known, but civil aviation spokesman Samuel Adurogboye said the aircraft "ran into bad weather".
NIGERIA PLANE CRASHES October 2005: Bellview Airlines plane crashes near the rural town of Kishi, Oyo state, killing 117 people May 2002: Plane operated by EAS Airlines crashes in Kano, killing 148 people - half of them on the ground November 1996: 142 people die when Boeing 727 owned by Nigeria's ADC airline plunges into lagoon 85km (55 miles) from Lagos September 1992: 158 people are killed when military transport plane goes down near Lagos
Air disasters timeline
"Almost everyone was killed. There was a lot of flames," said an airport official.
"There were many students onboard, returning for the holidays."
Mr Adurogboye said seven people were rescued.
"They were breathing and were taken to hospital. They are responding to treatment," he said.
He did not say if they were passengers or crew members.
A distraught mother awaiting news of her child at the Port Harcourt airport said the plane was carrying 75 secondary school students from a Jesuit college in Abuja.
Safety concerns
A Boeing 737 aircraft crashed in October shortly after take-off from the commercial capital Lagos, killing all 117 people on board.
The flight recorders from that plane were never found.
President Olusegun Obasanjo had instructed his aviation minister to plug any loopholes to ensure airline safety.
Correspondents say Nigeria's aviation industry has grown rapidly in recent years, but many aircraft are elderly and there have been several fatal crashes.
However, Sosoliso was regarded as one of the safer domestic Nigerian airlines.
A DC-9, such as the one pictured here, crashed in Nigeria.
A DC-9, operated by privately owned, Sosoliso Airlines, crashed in Port Harcourt, Nigeria, reportedly killing at least 103 people. Seven people are reported to have survived the crash.

Landing during an electrical storm, the plane overshot the runway and burst into flames. The aircraft broke into three main pieces, scattering passengers and wreckage.

Some 75 children returning home for the holidays are among the victims.