This work aimd at correlating the levels of plasma homocysteine (Hcy) and its related metabolites (S-adenosylhomocysteine (SAH) and S-adenosylmethionine (SAM)) on one hand , and the severity of essential hypertension (EH) on the other . It also aimed at investigating their possible role as risk factors for thrombovascular complications . Plasma folic acid and vitamin B12 were evaluated to clarify their role in Hcy-methionine interaction in pathogenesis of EH. This study was conducted on 65 patients suffering from EH. Patients were divided into 2 groups; group I (uncomplicated EH; IA=moderate, IB= severe) and group II (complicated EH; renal and non-renal ie coronary heart disease (CHD), cerbro-vascular strokes (CVS)) Fifteen healthy age and sex matched subjects were included as controls (groupIII).