"No Smoking" signs are now posted on hospital grounds.
The ban includes the main campus on Riverside Drive in Binghamton, and all of Lourde's off-site locations.
Lourdes first banned patients from smoking in 2004, and now employees cannot smoke either.
"This benefits everyone. It's great for the community to have a healthcare facility where people can go and have a smoke free environment," said Celeste Ridler of Lourdes Hospital.
Lourdes hopes going smoke-free will encourage employees to quit smoking.
The hospital is providing counseling and support groups.