The authors examine the use of population registers in the production of demographic statistics. "To do this, we first describe these registers; we then examine their further development as an independent source of population statistics--including current population estimates, vital and migration statistics--and as an alternative to population censuses. In conclusion, we consider a number of essential features of registers, including the original collection of data, the system's lifetime, privacy protection, and the government's ability to bring about a balance among conflicting interests regarding the collection and use of the data." The discussion is illustrated using examples from the Netherlands and Denmark.