BACKGROUND: According to epidemiological and metabolic studies monounsaturated fatty acids (MUFAs) seem to exert a protection against coronary heart disease (CHD) risk. The aim of the present study was to evaluate the association between the pattern of edible oils and fats consumption and the prevalence of a first, nonfatal event of an acute coronary syndrome (ACS) in a Greek sample. METHODS: Seven hundred males and 148 females patients with first event of an ACS and 1078 population-based controls, age and sex matched, were randomly selected. Detailed information regarding their medical records, alcohol intake, physical activity and smoking habits was recorded. Nutritional habits were evaluated with a semi-quantitative food-frequency questionnaire and use of oils in daily cooking or preparation of food was also recorded. Multiple logistic regression analysis estimated the odds ratio (OR) of having ACS by types of oil used, after taking into account the effect of several confounders. RESULTS: Exclusive use of olive oil was associated with 47% (95% confidence interval (CI) 0.4-0.71) lower likelihood of having ACS, compared to nonuse, after adjusting for BMI, smoking, physical activity level, educational status, the presence of family history of CHD, as well as hypertension, hypercholesterolemia and diabetes. Consumption of olive oil in combination with other oils or fats was not significantly associated with lower odds of ACS compared to no olive oil consumption (p=0.14). CONCLUSIONS: Exclusive use of olive oil during food preparation seems to offer significant protection against CHD, irrespective of various clinical, lifestyle and other characteristics of the participants.