Mrs. Olubunmi Odumusi died in her sleep on Friday night, her family said. She was 57.
Relatives said she died after a prolonged battle with cancer, after being at treated local and foreign hospitals at a huge financial cost.
Mrs. Odumusi, a journalist, joined the civil service and rose the position of director in the state Ministry of Information and Strategy.
She was in the United States of America for medical treatment when she received the news of her promotion as Permanent Secretary. She flew back to attend the inauguration and attended the event on wheelchair on Thursday.
As news of her passing spread Saturday, sympathisers thronged the family home at Sam Ewang Estate in Abeokuta.
Her heartbroken husband wept, clasping the body of his departed wife. The body was later taken to the Neuro Psychiatric Hospital.
A family source said Mrs. Odumusi went to bed on Friday, but failed to wake up in the morning.
Reacting to the death, former Governor Gbenga Daniel praised Mrs. Odumusi as a “gem” and said she was very hardworking in his administration.