Between 1973 and 1978, the Indonesian Government constructed over 61 000 primary schools throughout the country.This is one of the largest school construction programs on record. I evaluate the effect of this program on education and wages by combining differences across regions in the number of schools constructed with differences across cohorts induced by the timig of the program. The estimates suggets that teh construction of primary schools led to an increase in education and earnings. Children ages 2 to 6 in 1974 received 0.12 to 0.19 more years of educatioin for each school constructed pe 1000 children in their region of birth. Using the variations in schooling generated by this policy as instrumental variables fr the impact of education on wages generates estimates of economic returns to education ranging from 6.8 percent to 10.6 percent.