Over 100 raids were carried out on 28-29 June by the Slovakian Financial Administration, the government body tasked with licensing gambling operations, The Slovak Spectator reported.
The venues are reportedly sealed off and will be inspected further. The machines seized include 75 gaming machines and five quiz machines.
In Slovakia, the Tax Office monitors gambling license compliance and keeps a central register of the country's gambling operators.
Ľudovít Makó, head of the Financial Administration’s criminal department, reportedly stated the raids were a result of a tip concerning the use of quiz machines to gamble, in some instances by underage players.
The crackdown is part of a wider effort in the country to tackle illegal gambling operations.
According to the Slovakia Association of Entertainment and Gambling, there were 210 fines handed out to gambling operators in 2017 compared to 57 in 2016.
A gambling ban, which also saw a period of no new gaming licenses handed out, was introduced by city councillors in Bratislava in May 2017. It was overturned by the Regional Court on 7 June.