Police arrested two men and issued 50 fixed penalty notices in a crackdown on unlicensed taxi drivers in Sheffield and Doncaster.
As part of the operation taxis were also inspected to assess their roadworthiness.
A number of drivers were given prohibition notices to make sure defects on their vehicles are repaired.
They were warned that if they fail to carry out the repairs their taxis could be seized.
Police said the two men arrested in the crackdown were quizzed on suspicion of drink driving and failing to appear at court.
Chief Inspector Glen Suttenwood, head of the Roads Policing Unit in South Yorkshire, said: “This operation was a great opportunity for us to work alongside our partners and reinforce the importance of taxis being properly licensed and safe for passengers.
“The majority of drivers had the right documentation and vehicles were roadworthy but we have taken steps to address those that weren’t which will improve public safety.
“The operation was met with positive feedback from the drivers themselves and also their passengers. I would like to thank those involved for their support and co-operation throughout.”