Diabetes mellitus is associated with disturbances in haemostasis that could contribute to the development of thrombotic complications.The present study was undertaken to determine the behavior of coagulation variables and fibrinolytic system in diabetes mellitus. Forty five diabetic patients and forty five matched controls were evaluated by doing the following haemostatic parameter, prothrombin time, partial thromboplastin time, thrombin time, coagulation factors assay II, VII, IX, & plasma fibrinogen, ADP-induced platelet aggregation, protein C, a2- antiplasmin, PAI and FDPs. Generally diabetic patients have high levels of fibrinogen, a2- antiplasmin, & PAI and lower level of protein C. Other haemostatic parameters did not show statistically significant difference between diabetic patients and control group. Significantally elevated levels of PAI, a2- antiplasmin together with low protein C level in diabetic patients may result in the disturbance of haemostatic balance favoring thrombotic events. Conclusion: High levels of plasma fibrinogen, a2A- antiplasmin with low plasma protein C activity could lead to a prothrombotic tendency in insulin dependent diabetic patients. Moreover, in non-insulin dependent diabetic patients, the above mentioned parameters together with high levels of ADP-induced platelet aggregation and plasminogen activator inhibitor may increase the risk of thrombotic complications. Obesity can be considered as an additional risk factor for development of thrombosis in diabetic patients.