Chadbourne & Parke has become one of the first US firms to promote a part-time associate to partner.
The New York-based practice has promoted part-time associate Marian Baldwin to the partnership.
The part-time programme for associates was introduced several years ago but this is the first time a lawyer on flexible hours has become a partner.
Operations partner Charles O'Neill says the firm was left with no choice if it wanted to retain the best lawyers. He adds: "All firms are going to have to be flexible and adapt if they are going to keep good lawyers, particularly excellent female lawyers."
Baldwin, who has a young family, is a corporate partner and works in a transaction-heavy practice area.
But O'Neill says that this is not a problem. "If there is a major deal going down, Marian is very flexible, works like crazy and is there with everyone. Then she will take the time off," he says.