Background: Cardiovascular disease is the major cause of death in patients with diabetes mellitus. Microalbuminuria (MAU) is defined as persistent subclinical elevation of urinary albumin excretion rate (UAER), which is insufficient to be demonstrated by reagent strips. Objective: to determine the correlation between microalbuminuria and the severity of coronary artery stenosis assessed by Gensini score in patients with type II diabetes mellitus Patients and methods: This study included sixty-one patients with type II diabetes mellitus and suspected coronary artery disease that underwent elective coronary angiography in Al-Azhar University Hospital, New Damietta, during the period between October 2013 and October 2014. Patients were classified into two groups based on the level of urinary albumin: creatinine ratio (UACR): Group I included 32 patients (52.5 %) with microalbuminuria (UACR level ranging from 30 to less than 300 mg/g), and Group II included 29 patients (47.5 %) with normoalbuminuria (UACR level less than 30 mg/g). All patients were subjected to full history taking,clinical assessment, standard 12-lead surface electrocardiogram (ECG), echocardiography,laboratory investigations, andcoronary angiography. Results: This study showed that UACR and Gensini score increased with age. There was a significant positive correlation between UACR and total cholesterol, triglycerides, LDL-C and glycosylated hemoglobin (HgbA1c), while there was a significant negative correlation with HDL-C and smoking. There was a significant positive correlation between Gensini score and urinary albumin level. The Gensini score was correlated with LDL- C and no correlation with total cholesterol, triglycerides, HDL-C and glycosylated hemoglobin (HgbA1c) or smoking. In the present study, the number of coronary vessels affected was higher in patients with microalbuminuria than those without microalbuminuria. The severity of coronary artery disease assessed by Gensini score was significantly higher in patients with microalbuminuria than those without microalbuminuria, and there was a correlation between UACR and Gensini score as a measurement of severity of coronary artery stenosis. Conclusion: In patients with type II DM, microalbuminuria can be used as a predictor for coronary artery disease severity.