Background: Despite of long history of Expand program of immunization service delivery and most countries in the world achieved immunization coverage of around 90% for DPT3 in 2010, still there is child mortality attributed to vaccine preventable disease which accounts 29% of world-wide. This problem is attributed to reduced vaccine potency due to failure in cold chain monitoring system. Cold chain monitoring is still a major challenge in developing countries including Ethiopia. The aim of this study was to assess cold chain status and knowledge of vaccine providers at primary health care units.