Diabetes mellitus is one of the common health problems. It has many serious complications among them are hypertension and diabetic nephropathy which may lead to renal failure. The first sign of early stage renal of failure or diabetic nephropathy is proteinuria which {presence of an abnormal amount of protein in urine} which leads to hypertension. As its known that hypertensive patients need treatment and those with diabetes and proteinuria need more attention to be given during choosing their antihypertensive medications by using effective drugs with less side effects and comply with many aspects that are looked for by both the physician and the patient. This study was conducted on {28} diabetic patients using insulin for treatment , those patients were newly diagnosed to have hypertension as a complication of diabetes. The medications that are used as antihypertensive for them are either angiotensin converting enzyme inhibitors{ACEI} or Atenolol{tenormin}. According to the antihypertensive drugs used for treatment they were classified into two groups :Group-A- ACEI patients, and group-B- Atenolol patients. The aim of this study was to find whether Atenolol has an effect on proteinuria or not and to compare this effect if any with ACEI, despite the fact that ACEI has a renoprotective effect on kidney but because Atenolol became widely used for the management of hypertension whatever the aetiology of hypertension. As it is known well that for every medication there are side effects some of them might be serious so Atenolol needed to be used cautiously in diabetic patients because it causes masking of hypoglycemia in addition to other side effects but its widely used by our physicians in diabetic patients so we want to demonstrate here whether it has an effect on the level of proteinuria which might be a cause, or a result of hypertension in diabetic patients, in order to decrease the unwanted side effects on those patients and to pay more attention during choosing the medications used for such patients. Therefore {24} hour urine was collected for each patient and total protein in urine was measured before starting treatment and after different periods from using medications, in addition to monitor blood pressure and blood glucose levels.From the results obtained it was clear that ACEI still the effective drug, it significantly( p < 0.05) lowers both blood pressure and the level of proteinuria in contrast to Atenolol which was not significant in lowering the level of proteinuria but effectively lowered blood pressure .It was concluded that ACEI still the best to be the first choice medication for diabetic hypertensive patients, while Atenolol needs more attention and follow up for the patients when its decided to be used.