Objectives: the aim of the present study was to provide guidelines for optimal Warfarin anticoagulation in Sudanese patients after mechanical heart valve replacement undergoing to Cardio Pulmonary Bypass. Methodology: A Carbomedics valve was implanted in 80 patients between July 2006 and July 2008. The INR calculate direct from the machine using coagulation analyzer model  Bio – Bas.1,

Results: The mean international normalized ratio (INR) was 2.8± 0.38, however there was a significant variation (p. value