The Pacific island countries are at different stages of the demographic and epidemiological transitions. The availability of accurate and current mortality data is of vital importance for setting priorities in the field of health. Available mortality data generally under-estimate death rates, both among children and adults. This article reviews available life expectancy and infant mortality information reported by countries from the late 1990s to 2005, evaluating it with respect to quality, and a final "best estimate" established. The article finds that in some countries, life expectancy variations of 10 years or more were recorded, depending on the source. Best approaches suggest that life expectancy (at birth) varied considerably from levels around 55-60 years in some Melanesian and Micronesian States to levels greater than 70 years in low mortality countries. Principal issues with regard to uncertainty around mortality levels include: under-enumerated vital registration data; annual stochastic fluctuations in mortality in small populations; errors in the imputation of adult mortality from infant and childhood rates; implausible results from indirect demographic methods; use of possibly inappropriate model life tables to adjust death data, or for indirect methods; and inadequately described and implausible projections. The article highlights the urgent need for improved infrastructure, training and resources for routine mortality estimation in many Pacific island countries in order to better inform and evaluate health and public policy.