Corruption as a vice continues to dog the efficient delivery of public services in most countries. While developed countries have made great strides in curbing the vice with mixed results, in developing countries it continues to sniff-out scarce resources needed for provision of essential services such as education, health, water among others. Defined by the public service in Kenya as an act of using one's position in office for self gain, corruption has been said to be deeply embedded in the life of many public agencies. Reasons such as self-aggrandizement, emergence of a materialistic culture and appetite for quick wealth have been cited as possible causes of corruption; these have led most people to fear that the vice might transform into an incurable cancer that is openly tolerated. This paper presents finding from a survey detailing why corruption remains a major impediment to efficiency and effectiveness of public service delivery in spite of the many legal, judicial and institutional initiatives implemented to fight the vice. The paper answers the question: What challenges are managers in the public service facing in combating corruption? It finally presents the lessons from Kenya's experience have for public administrators especially in the developing countries?