Background: this study was undertaken to study the biochemical effects of lipoproteins and apolipoproteins on uncontrolled Egyptian patients with type 2 diabetes mellitus, and to study if Apo B100/Apo A1 ratio can be used as a predictive factor for assessment of CAD risk in this patients. Patients & Methods: this study was carried out on a group of 60 patients; 20 were non diabetic controls and 40 diabetic patients, who were subdivided into : controlled type 2 diabetic patients (Group I) and uncontrolled type 2 diabetic patients (Group II), based on their glycated hemoglobin level. Levels of triacylglycerols or triglycerides (TG), total cholesterol (TC), HDL-C, Apolipoprotein A1 and Apolipoprotein B100, in addition to fasting blood glucose (FBG) and glycated hemoglobin (HbA_1c) were estimated,and also, levels of LDL-C were calculated by Friedewald's formula in all studied cases. Blood samples were collected after an overnight fasting of 10-12 hours, and divided into two parts, the 1^st  for separation of serum and the 2^nd collected in an EDTA-containing tube for HbA_1c determination. Results: the obtained results revealed that, levels of total cholesterol, LDL-C and Apo B100 were comparable with no statistical significance between uncontrolled type 2 diadetic patients (group II) with controlled type 2 diabetic patients (group I) and control group.While, a highly significant increase in triacylglycerols levels in group II compared to group I and control group. In contrast, a highly significant decrease in HDL-C and Apo A1 levels in group II compared to group I and control group. Highly significant increase in Apo B100/Apo A1 ratio in group II compared to group I, and a significant increase compared to control group, while it was comparable with no statistical significance in group I compared to control group. Conclusion: this study showed that there was an adverse effect of prolonged hyperglycemia on the apolipoproteins in diabetic patients which is associated with dyslipidemia, good glycemic control is able to make an improvement on this dyslipidemia. Apo B100/Apo A1 ratio can be used as a predictive parameter for assessment of CAD risk in type 2 diabetes mellitus.