Hyperhomocysteinemia and hyperactivity of the angiotensin-1 converting enzyme (ACE1) are considered two unconventional coronary risk factors. The study of the variation of these two biochemical parameters in coronary patients and metabolic investigation of the relationship between these two markers has a fundamental interest. In this context, 110 patients and 80 control subjects are recruited for our study. Homocystenemia was determined by fluorescence polarization immunoassay (FPIA). ACE1 activity was measured by kinetic method. An increased of homocysteinemia and ACE1 activity was observed in patients compared with control subjects (Hcy: 23±18 μmol/L vs 9±4 μmol /L; p<0.0001); (ACEI: 81±18 UI/L vs 55±18 UI/L; p<0.0001). These two markers varied differently according to the risk factors. Homocysteinemia, was negatively correlated with ACE1 activity (r = -0.36; p<0.001). The negative correlation between these two markers reflects metabolic and physiopathological interactions.