The aim of this study was to evaluate conjugated dienes in subjects with non-insulin-dependent diabetes mellitus (NIDDM) and its metabolic control. To achieve good metabolic control in addition to dietary management oral hypoglycemic agents such as glibenclamide, gliclazide and metformin were given to patients. Human plasma low-density lipoproteins (LDL) were delipidised and triglycerides (LDL-TG) and cholesterol esters (LDL-CE) were separated. Conjugated dienes in LDL-TG and LDL-CE of subjects with NIDDM (n = 90) and normal glucose tolerance (NGT) (n = 30) were measured using second derivative of uv absorption spectrum. Hypoglycemic agents lowered substantially concentration of cis, trans (c, t) and trans, trans (t, t) conjugated dienes in LDL-CE and LDL-TG. The duration of NIDDM has shown significant correlation (p < 0.001) with conjugated dienes in LDL-TG. Concentration of c, t and t, t-conjugated dienes in LDL-CE and LDL-TG were found significantly higher in subjects with NIDDM than NGT (p < 0.001). In conclusion, NIDDM, status of metabolic control and duration of diabetes have strong positive relation with oxidative stress.