Kitui West MP Francis Nyenze carried an oxygen tank into the chambers for his swearing-in.
Mr Nyenze arrived at about 10am dragging the tank behind him, with the tubes snaking up his back.
The former minority leader appeared to have been taken ill.
He looked frail and was limping but put on a brave face and greeted the battery of journalists at the entrance.
He said: “How are you are friends…mimi pia nimefika (I’ve also made it) for the swearing-in.”
He hugged and cheerfully greeted his colleagues inside and took the oath.
His voice sounded frail.
The Nation could not immediately establish the nature of his illness.
Babu Owino adds “Raila Amolo Odinga” and “Tibim” to his oath.