The trace element selenium is an essential micronutrient for human health, and its low levels in serum are implicated in the pathogenesis of several chronic diseases. The determination of total serum selenium levels may contribute to the assessment of the health status of all populations. Since the serum selenium levels are highly affected by diet, we assessed its association with the dietary habits of Greek adults.Serum selenium levels were determined with inductively coupled plasma mass spectrometry in a cohort of 506 participants (men: 296, women: 210) aged 18-75 from the ATTICA study. Food consumption was evaluated with a validated food-frequency questionnaire.Evaluation of the relationship between serum total selenium with major food groups and beverages by multi-adjusted analysis revealed that serum selenium was positively correlated with the consumption of red meat (2.37 ± 0.91, p = 0.01) while the consumption of other selenium-containing foods (i.e., fish, cereals, dairy products, vegetables) did not demonstrate such a relationship. Moreover, principal component analysis revealed that the adoption of a vegetarian type of diet is inversely correlated with total selenium (-3.94 ± 2.28, p = 0.08).Among the dietary habits that were examined, red meat seems to be the major determinant of serum selenium in Greek adults.