Workers covered by defined benefit pension plans receive lower benefits at retirement if they leave their current jobs before reaching retirement age. This study estimates the magnitude of this pension loss for workers in the May 1983 supplement of the Current Population Survey, using pension formula estimates from the 1983 Employee Benefit Survey. The pension loss is generally greatest between the ages of 35 and 54 and represents roughly half of a year's earnings for that age group. The loss tends to be quite high in the declining mining and manufacturing sectors. This probably resulted in lower voluntary attrition at a time of massive layoffs and plant closings.