Hollywood Presbyterian Medical Center officials were forced to pay about $17,000 in bitcoins to get their computer systems back online.
Staff at the hospital noticed issues accessing its computer network on February 5.
Malware had locked access to certain computer systems and prevented staff from communicating electronically, the hospital said in a statement.
“The quickest and most efficient way to restore our systems and administrative functions was to pay the ransom and obtain the decryption key,” said Allen Stefanek, president of Hollywood Presbyterian Medical Center, in a statement. “In the best interest of restoring normal operations, we did this.”
The system required 40 bitcoins to regain access, or nearly $17,000.
Stefanek said the electronic medical records system was restored Monday.
The hospital has contacted law enforcement and is working with a team of experts to understand how the attack occurred.
The FBI said it is investigating the incident.
No further details are available at this time.