The Mediterranean diet has been postulated as a model for the prevention of coronary heart disease. The SUN project ("Seguimiento Universidad de Navarra") is an epidemiological prospective cohort study of University of Navarre alumni started in 2000 with the main objective of identifying dietary and non-dietary determinants of these disorders. The feasibility of the project was verified in a two-phase pilot study.Volunteers participated in the first phase of the pilot study. Dietary and non-dietary exposures were measured using self-administered questionnaires and interview. A random sample of 600 graduates was selected for the second phase of the pilot study. The selected alumni received a questionnaire by mail. The 10th, 25th, 50th, 75th and 90th percentiles were calculated for the consumption of each food item or nutrient to estimate the inter-subject variability.The participants understood and answered the questionnaires properly. The mean time spent in completing the questionnaire was 55 minutes (95% CI: 50.7-59.3). A wide inter-subject variability was found in the consumption of food items considered as more representative of the Mediterranean diet (olive oil, fruits, vegetables and wine) with major differences between the 10th and 90th percentile. A Mediterranean diet pattern was found with a wide inter-subject variability.The response rate was acceptable. This finding is likely to ensure the identification of associations between the consumption of given food items and the occurrence of the main outcomes we are targeting.