The Driver and Vehicle Licensing Agency (DVLA) has finished an inquiry into the circulation of "inappropriate" e-mails, some pornographic, at its offices.
The DVLA said pornography was downloaded from the internet
It said a total of 18 people were dismissed and a further 147 officially reprimanded as a result.
The agency, which employs more than 5,000 people in Swansea, said the matter was now "officially closed."
The inquiry was launched in March 2006 when pornographic images were downloaded from the internet.
They were then circulated amongst staff.
IT experts pinpointed which of the DVLA's staff were using the machines involved at the time.
Those dismissed were found to have downloaded or sent pornographic material.
Eleven of them appealed but their claims were dismissed.
The other 147 were disciplined for sending "inappropriate material" but not pornography and received various degrees of reprimand, including final warnings.
A spokeswoman for the DVLA said all staff had been reminded about the rules governing the use of work e-mails.
"The matter is now officially closed," she added.