Officers carried out a warrant at an address in Hadley Park Road in Leegomery on Monday, July 15.
A 54-year-old man was arrested on suspicion of firearms offences and has been released on police bail.
Along with an illegally imported firearm, a number of replica firearms were also seized.
The warrant saw police work in partnership with the National Crime Agency.
Detective Sergeant Simon Dunn, from Telford CID, said: "We do not have an issue with gun crime in Telford but where information comes to light someone may be illegally in possession of a firearm we will take action to seize the weapon.
"In some instances, simple conversion techniques allow individuals without expert knowledge to transport low cost blank firing weapons into lethal firearms.
"Firearms supply through European channels is common and we will continue to work with our partners, such as the National Crime Agency, to disrupt and tackle the supply chain."