Homocysteine (Hcy) is recognised as a risk factor for IHD. Serum Hcy is negatively correlated with serum folate levels, the main sources of which are fruits, vegetables and legumes. The present case–control study was designed to examine the relationship between serum Hcy levels and IHD and to assess the role of dietary factors in the southern Mediterranean population of Crete, Greece. Serum Hcy, folate, vitamin B12, creatinine and glucose levels and a full lipid profile were measured in 152 patients with established IHD, median age 64 (range 33–77) years, and 152 healthy control subjects, age- and sex-matched. Dietary data were assessed using a 3 d food intake record. Compared with controls, patients with IHD had significantly higher daily intakes of vitamin B12 and MUFA and significantly lower intakes of carbohydrate, fibre, folate, cholesterol, n-3 fatty acids and total trans unsaturated fatty acids. Moreover, patients had significantly higher serum Hcy, vitamin B12 and creatinine levels, but significantly lower folate. Serum folate concentrations in both groups had a significant positive correlation with dietary fibre consumption and a significant inverse correlation with vitamin B12 intake. IHD patients should be encouraged to increase their daily dietary intake of fibre, folate and n-3 fatty acids, which are significant components of the traditional Cretan Mediterranean diet. Where dietary folate intake is inadequate, folate supplements are recommended to reduce elevated Hcy levels.