Background: In the two decades since reunification, East Germans have experienced a large increase in life expectancy and a convergence with the West German mortality level. This gain in life expectancy appears even more impressive if we assume a different scenario in which the Berlin Wall did not fall, and the old East Germany still existed. Objective: This analysis takes into account that East German mortality would not have remained static without reunification. Thus, it shows how many years of life expectancy were actually added by the fall of the Berlin Wall. Method: The analysis shows the improvements for single age groups by projecting life expectancy based on mortality levels during the 1970s and 1980s using the Lee-Carter method. I use national-level data for both sexes for East Germany before reunification. Results: I find that, without reunification, current life expectancy at birth among East Germans would be 4.0 years lower for females and 5.7 years lower for males. I also show that older East Germans were the main demographic beneficiaries of reunification. Female and male mortality improvements in the age groups above 60 contributed up to 80% to the actual gains in life expectancy. Conclusions: Had the Berlin Wall not fallen, East German mortality would not have remained static but improved at a far slower rate. Thus, this counterfactual approach shows for the first time how many years of life were actually gained by reunification and how much of these gains were attributable to mortality improvements among the elderly.