Verdic Lifecare Hospital in Lekki, Lagos, has asked all those who visited the facility in the last 10 days to go on self-isolation.
The hospital, in a statement on Monday, said it had admitted a patient who tested positive for COVID-19.
The patent was said to have tested positive after he was discharged, but two of the hospital staff had contracted the disease.
"We also had 2 staff members who tested positive yesterday evening. The patient and our staff are now being managed by the NCDC at their isolation centre," the hospital said.
"This moment they do not show any symptoms. All staff members have been maintaining mandatory PPE gear since the last 25 days. The facility is currently closed off for decontamination of the building. The fumigation was already carried out by NCDC on 18th April.
"We are currently testing the remaining staff members and will continue to update everyone on all platforms.
"If you have visited the hospital in the last 10 days, we request you to get tested and stay isolated."
About 627 cases of COVID-19 have been confirmed in Nigeria.