Italy's anti-trust watchdog said on Wednesday it was fining Apple and Samsung 5 million euros ($5.7 million) each following complaints they used software updates to slow down their mobile phones.
Apple was hit with an additional 5 million euro fine for failing to give clients clear information about how to maintain or eventually replace handset batteries.
Italian consumer groups had complained that software updates for mobile phones reduced the functionality of the devices and were designed to push clients into buying new handsets.
The anti-trust body said in a statement that some Apple and Samsung firmware updates "had caused serious dysfunctions and reduced performance significantly, thereby accelerating the process of replacing them."
It added the two firms had not provided customers adequate information about the impact of the new software "or any means of restoring the original functionality of the products."
Apple acknowledged last year that iPhone software had the effect of slowing down some phones with battery problems, but denied it had ever done anything to intentionally shorten the life of a product.
The company apologized for its actions and cut battery replacement costs. It has also said it would change its software to show users whether their phone batteries were working well.
Samsung's software updates for its phones have not previously been questioned.