Fraudsters are using the music device to record customers' bank details, allowing them to steal cash.
Police discovered an iPod Nano taped to the roof of a cash machine in St Vincent Street at the weekend.
They were called after a member of the public became suspicious while using the ATM.
The scam involves taping an iPod to the roof of a cash machine.
A loop of plastic is placed into the card slot, which then traps any card put in the machine.
Customers believe their card has been retained by the machine and when they walk away the thief removes the device and steals the card.
The thieves then watch footage from the iPod of the customer entering their personal identification (PIN) number.
Police on patrol in the city centre regularly check cash machines for signs they have been tampered with.
However, people were today being advised to take extreme care when using ATMs.
A Police Scotland spokesman said: "A device was found on an ATM in St Vincent Street in Glasgow city centre.
"An iPod Nano was attached above the keypad and used to record the PIN. Please take precautions when using ATMs, check ATMs for devices, and always shield your PIN.
"When people are using their card they should shield their PIN when they are using the keypad.
"Then, if there is a recording device attached, they are covering their number."
He added: "If you see anything strange or different about the machine, report it immediately to the bank or the police.
"And don't leave the machine unattended, as that is when the thief will approach and take your card."
Last month, the Evening Times told how thieves used a hi-tech skimming device to steal thousands of pounds from people in a city suburb.
Police discovered the sophisticated equipment at a cash machine in Giffnock, East Renfrewshire. It was found at an ATM in Fenwick Road and £3000 was stolen from a customer's bank account.
It was the second time in two months that Giffnock residents had been targeted.