This paper examines the measurement of infant mortality in the countries of Central and Eastern Europe and the Commonwealth of Independent States. There are worrying indications that official infant mortality counts, based on administrative data, may understate the true gravity of the problem in 15 countries in the region, including 11 out of 12 CIS countries, and four countries in South Eastern Europe. In the case of eight CIS countries in the Caucasus and Central Asia plus Romania, the evidence is strongest, not least because surveys that allow independent estimation of infant mortality have been carried out there. In the case of the remaining six countries, the evidence is more circumstantial, and based on inconsistencies within the official data themselves, combined with information on how live births are defined. However, the paper also finds that surveys are rather blunt instruments, and that the confidence intervals that surround estimates from these surveys are often large. Further work needs to be done, not only to improve the collection of official statistics on births and infant deaths in many countries across the region, but also to improve the effectiveness of surveys as a measurement tool.