The town's safer neighbourhood team has warned that forged currency is being circulated at shops in the area.
Residents and traders in the town are being urged to stay vigilant and be aware when taking large value notes.
Oswestry Safer Neighbourhood Team tweeted: "Please be aware that a fake £50 note has been tendered in Oswestry.
"Use due diligence in accepting monies."
Please be aware that a fake £50 note has been tendered in Oswestry. Use due diligence in accepting monies.— Oswestry SNT (@OsCops) February 13, 2020
Anyone with any information or witnessing anything suspicious should contact police on 101.
Alternatively, contact Crimestoppers anonymously on 0800555111 or crimestoppers-uk.org