CINCINNATI (AP) _ Legal fees are approaching $90 million in the 17 months since Federated Department Stores Inc. and Allied Stores Corp. filed for Chapter 11 bankruptcy protection, a court trustee said.

''We've tried to control the fees,'' said bankruptcy court trustee Conrad Morgenstern, explaining that the largest retail bankruptcy in U.S. history has involved numerous hours of work by attorneys.

The companies, owned by the Campeau Corp. of Toronto but headquartered in Cincinatti, operate such retail stores as Bloomingdale's in New York, Jordan Marsh in Boston and Lazarus in Ohio.

Morgenstern said that if it takes $100 million in legal fees to bring a $10 billion company out of bankruptcy, that represents only 1 percent of the company's assets.

''... They (lawyers) are entitled to receive what their charges are,'' he said. His remarks were reported in an interview with the Cincinnati Enquirer, published Saturday.

Morgenstern said Allied's law firm listed 240 staff members logging 18,080 hours working on the bankruptcy in the first quarter of 1991.

Attorney David G. Heiman, who gets $300 an hour, charged 521.4 hours in January, February and March. The busiest was $135-an-hour associate Scott Davido, who logged 684.5 hours in the period, Morgenstern told the newspaper.