The agency has been briefed to devise a TV campaign to attract footfall and sales in the UK in the hugely competitive run up to the Christmas period and the January sales.
Golley Slater chief executive Chris Lovell said: "Euronics is Europe's leading buying group in consumer electronics.
"Aside from the advertising campaign, we will also be redesigning the website and point of sale to tie in with the TV campaign."
The retailer's most high-profile television campaign to date featured the star of BBC's Airport, Jeremy Spake.
As part of the new focus, Spake has been dropped, with a replacement coming in the guise of a computer generated character.
A new national television campaign starts at the end of November.
"Jeremy did a great job but we've decided to move on," a Golley Slater spokesman said.
Golley Slater is a full-service agency that has previously worked for retail clients such as HMV, Furniture Village and Principles.
Founded in 1990, Euronics now has 8,900 stores worldwide, employing more than 42,000 people.