Among the hospitals affected were emergency rooms and children’s centers; as a precaution, additional institutions went offline.
The hackers demanded 3.5 Bitcoin, which is more than £130,000, in order to open important files that they had encrypted.
However, data had recently been backed up, according to Romanian cyber officials, lessening the effect.
According to a statement from the Romanian Ministry of Health, the attack mostly took place overnight on Monday and was directed towards a popular medical information system.
According to the ministry, cyber security specialists from the National Cyber Security Directorate (DNSC) were among the IT specialists looking into the situation.
The Pitesti Paediatric Hospital was the first of 25 hospitals reportedly impacted by the hack, according to the DNSC.
According to the organization, 79 additional healthcare facilities were placed offline while inquiries were made to see whether they were also impacted.
Although the type of malware employed has been identified by officials, the group responsible has not yet been found. Officials wrote that the ransom demand merely has an email address.
It is anticipated that the hospitals would be able to recover fairly quickly because the majority of the institutions that are being targeted have recent backups of their data from the compromised servers.
However, because dozens of additional institutions were forced to turn off internet-connected devices out of prudence, the effect on patients is probably going to be significant