The Treasury Department and the IRS made final regulations under IRC sections 401(k) and 401(m) that allow sponsors to design retirement plans in which employees can make designated Roth IRA contributions. As a result, workers can choose to make all or part of their 401(k) deferrals on an after-tax basis, so that the qualified distribution of those contributions and their earnings will be tax-free. The regulations took effect January 3, 2006, and apply to plan years beginning on or after January 1, 2006 ( www.treas.gov/press/releases/js3068.htm ).