This document contains final regulations prescribing mortality tables to be used by most defined benefit pension plans. The tables specify the probability of survival year-by-year for an individual based on age, gender, and other factors. This information is used (together with other actuarial assumptions) to calculate the present value of a stream of expected future benefit payments for purposes of determining the minimum funding requirements for a defined benefit plan. These mortality tables are also relevant in determining the minimum required amount of a lump-sum distribution from such a plan. In addition, this document contains final regulations updating the requirements that a plan sponsor must meet to obtain IRS approval to use mortality tables specific to the plan for minimum funding purposes (instead of using the generally applicable mortality tables). These regulations affect participants in, beneficiaries of, employers maintaining, and administrators of certain retirement plans.