Spokeswomen for both firms said they could not immediately comment. Sources familiar with the discussions asked that their identities not be revealed.
It is unclear which firm will absorb the other, or whether the Ice Miller name will remain. Ice Miller is the larger firm, with 263 attorneys; Greenebaum Doll has 180 lawyers.
Ice Miller has 238 of its lawyers downtown in One America Tower. It also has offices in Washington, D.C., Chicago and the Chicago suburb of Lisle.
Besides Louisville, Greenebaum Doll has Kentucky offices in Covington, Frankfort and Lexington, and others in Cincinnati and Nashville, Tenn.
Ice Miller was founded in 1910 and counts Eli Lilly and Co., Indianapolis Motor Speedway and Clarian Health among its major clients.
Greenebaum Doll was established in 1952.
This would be the second merger involving a major Indianapolis firm within the past year. In May, Sommer Barnard PC became part of Taft Stettinius & Hollister LLP in Cincinnati.