Objective: The aim of our study was to investigate the association between salivary flow rate in diabetes mellitus and the development of coronary artery disease. Methodology: A cross-sectional study was executed in the Cardiology Department of Civil Hospital Karachi. Unstimulated saliva was collected between 9 and 11 a.m. Participants were asked to refrain from eating and drinking for 1 hour before saliva collection. They were then instructed to collect 5 ml of unstimulated saliva in a 15 ml falcon tube for 10 minutes. Finally, the patient’s oral hygiene status was recorded by a dentist. Data was entered in SPSS version 21. Descriptive analysis and significance of relationship was analyzed using chi-square test. Results: Out of 100 myocardial infarct patients between the age range of 30-70 years, 71(71%) were male and 29 (29%) were female. Overall frequency of diabetes mellitus was 55%. Significant relationships were found between occurrence of myocardial infarction in diabetes mellitus, among salivary flow rate reduction and age of the patient, and salivary flow rate reduction and gender of patient Salivary flow reduction below 3mL/10 minute was found in 48 diabetic patients whereas 11 nondiabetic patients had this clinical finding. No significant relationship was found between occurrence of caries and periodontitis with presence of diabetes. Conclusion: Careful monitoring of the oral symptoms related to severity of DM particularly the salivary flow rate can be helpful in early diagnosis of patients at possibility of developing cardiovascular complications. Keywords: Myocardial infarction, unstimulated saliva, Type II DM, Salivary flow rate.