Lawson will replace Patricia Killen, who resigned after being elected in April 2006, and will lead the development of the organisation, which marks its 10th anniversary in September.
Lawson said she was "very sorry" that Killen had resigned from leading Fedma, but that her predecessor's work had "already set the strategies for Fedma and we are enormously grateful to her for her hard work and dedication".
Fedma, which represents the European direct marketing industry, has more than 200 direct marketing companies listed as members of the organisation.
According to the body, the European direct marketing industry has an annual expenditure of more than €1bn (£670m), and employs more than 2m people across the continent.