Background: The fourth Millennium Development Goal (MDG) calls for a two-thirds' reduction between 1990 and 2015 in deaths of children younger than five years; achieving this will require widespread use of effective interventions, especially in poor countries. We present the first report of the Child Survival Countdown, a worldwide effort to monitor coverage of key child-survival interventions in 60 countries with the world's highest numbers or rates of child mortality. Methods: In 2005, we developed a profile for each of the 60 countries to summarise information on coverage with essential child survival interventions. The profiles also present information on demographics, nutritional status, major causes of death in children under 5 years of age, and the status of selected health policies. Progress toward the fourth MDG is summarised by comparing the average annual rate of reduction in under-5 mortality in each country with that needed to achieve the goal. The profiles also include a comparison of the proportions of children in the poorest and richest quintiles of the population who received six or more essential prevention interventions. Each country's progress (as measured by defined indicators of intervention coverage) was put into one of three groups created on the basis of international targets: "on track"; "watch and act"; and "high alert". For indicators without targets, arbitrary thresholds for high, middle, and low performance across the 60 countries were used as a basis for categorisation. Findings: Only seven countries are on track to met MDG-4, 39 countries are making some progress, although they need to accelerate the speed, and 14 countries are cause for serious concern. Coverage of the key child survival interventions remains critically low, although some countries have made substantial improvements in increasing the proportion of mothers and children with access to life saving interventions by as much as ten percentage points in 2 years. Children from the poorest families were less likely than those from wealthier families to have received at least six essential prevention interventions. Interpretation: Our results show that tremendous efforts are urgently needed to achieve the MDG for child survival. Profiles for each country show where efforts need to be intensified, and highlight the extent to which prevention interventions are being delivered equitably and reaching poor families. This first report also shows country-specific improvements in coverage and highlights missed opportunities. The "Countdown to 2015" will report on progress every 2 years as a strategy for increasing accountability worldwide for progress in child survival.