OBJECTIVE: The aim of this work was to investigate the association between fish consumption and the development of non-fatal acute coronary syndromes (ACS), in a Mediterranean population. METHODS: During 2000-2001, we randomly and stratified selected, from all Greek regions, 848 hospitalised patients (695 males, 58+/-10 years old and 153 females, 65+/-9 years old) who had a first event of ACS and 1078 paired, by region-sex-age, controls without any clinical symptoms or signs of coronary heart disease. RESULTS: On multivariate logistic regression analysis and, after controlling for several potential confounders, we found that fish consumption less than 150 g/week was associated with 38% lower odds of developing ACS as compared to no consumption (odds ratio=0.62, P-value<0.05). In contrast, moderate (150-300 g/week) and high (>300 g/week) fish consumption was not associated with the developing of the disease (odds ratios=1.10 and 1.01, respectively, P-value>0.1). The benefits from low fish consumption were also significant even amongst current smokers and diabetics. CONCLUSION: Moderate fish consumption was independently associated with a significant reduction in the odds of developing ACS. The strength and consistency of this finding has implications for public health and should be explored further.