Objective: How food is produced and consumed has consequences for ecosystems, such as resource use and greenhouse gas (GHG) emission among others. The Mediterranean diet (MedDiet) was proposed as a sustainable dietary model, due to its nutritional, environmental, economic and sociocultural dimensions. However, further evidence is needed. Thus, our objective was to evaluate the impact on resource (land, water and energy) use and GHG emission of better adherence to the MedDiet in a Mediterranean Spanish cohort. Design: We analysed the dietary pattern of participants through a validated FFQ. The outcomes were land use, water and energy consumption and GHG emission according to MedDiet adherence. The specific environmental footprints of food item production and processing were obtained from different available life-cycle assessments. Setting: Spanish university graduates. Subjects: Participants (n 20 363) in the Seguimiento Universidad de Navarra (SUN) cohort. Results: Better adherence to the MedDiet was associated with lower land use (-0.71 (95% CI -0.76, -0.66) m(2)/d), water consumption (-58.88 (95% CI -90.12, -27.64) litres/d), energy consumption (-0.86 (95% CI -1.01, -0.70) MJ/d) and GHG emission (-0.73 (95% CI -0.78, -0.69) kg CO(2)e/d). A statistically significant linear trend (P<0.05) was observed in all these analyses. Conclusions: In this Mediterranean cohort, better adherence to the MedDiet was an eco-friendly option according to resource consumption and GHG emission.