The company has worked with Citigate Albert Frank, the company that created the iconic widow character, for more than 20 years.
Citigate has been invited to take part in the review, which is being run through the AAR. A list of pitching agencies is currently being put together, with a result expected by the end of November.
Scottish Widows, which is owned by Lloyds TSB, is looking for an agency to refresh the famous widow icon rather than dispense with it.
Its media planning and buying account, held by ZenithOptimedia, is unaffected by the ad agency review. Earlier this year, Scottish Widows added the direct marketing agencies Navigator and Barraclough Edwards Chamberlain to its roster.
The review is being overseen by Rob Rees, Scottish Widows' interim customer and brand director. Rees was appointed after the company's marketing director Peter Jordan left in July.
Rees has held similar temporary positions at Campbells and Orange.
Alan Whiting, the head of brand development for Scottish Widows, said: "The Scottish widow has continued to be an incredibly effective advertising and brand icon and has really stood the test of time. We are now at the stage where we need to ensure that going forward it remains as relevant as possible and are therefore looking at the options available to us."