Background: Nurses knowledge concerning the Prevention of Central Venous Catheter Infection in intensive care units in hospitals is one of the main issues that nurses should know is to reduce or prevent patients' complications. Aims of study: Assess the Nurses knowledge concerning the Prevention of Central Venous Catheter Infection, to find out the relationship between the nurses knowledge with their demographic and occupational characteristics. Methodology: To achieving this objectives a questionnaire was developed according to review of literature and consist of two parts, the first part deal with demographic and occupational characteristic of intensive care unit nurses, while the second part include questions for knowledge test regarding prevention of central venous catheter infection,  Sample consist of (50) nurses who work in intensive care unit in: Ghazi Alhareri Teaching Hospital, Ibn Al-Bitar Teaching Hospital, Ibn Al-Nafis Teaching Hospital, Baghdad Teaching Hospital, Alkarama Teaching Hospital, AL-Kindy Teaching Hospital.The validity of the questionnaire was achieved through (13) of experts,(10) who working in Nursing college University of Baghdad and also(3)expert who work in Baghdad Teaching Hospital and Ibn Al-Bitar Teaching Hospital, The data collection instrument of choice was structure interview, the study starting from 15 December 2014 to 22 May 2015, collected data were analyzed with the assistance of a statistician using descriptive and inferential statistic.  Result: Show that the study of the research in regard to nurses age (52%) of them were in age group (20-29) years, and more than one half (58%) of them were female, (54%) were nursing college graduate with no training session in especially in intensive care unit, also reveals that the nurses' knowledge in fair level (54%). Conclusion: This study concludes that the most of the nurses had a fair level of knowledge.