About one-third of the disbursements from pension plans are in the form of lump-sum distributions. In this paper, we use tax-return data to study the incidence and disposition of lump-sum distributions. We find that most lump-sum distributions are small, and the probability of rolling a lump sum over is positively correlated with the size of the distribution. Also, although lower-income families are less likely to roll over any given-sized distribution, these families are less likely to receive significant lump sums in the first place so that nonrolled lump sums (leakage from the pension system) are not significant relative to income.