A 6-month intervention study with a quasi-experimental design was conducted to evaluate the effectiveness of an Internet-based, stepwise, tailored-feedback intervention promoting four key components of the Mediterranean diet. Fifty-three (intervention group) and nineteen (control group) healthy females were recruited from the Universities of Glasgow and Glasgow Caledonian, Scotland, respectively. Participants in the intervention group received tailored dietary and psychosocial feedback and Internet nutrition education over a 6-month period, while participants in the control group were provided with minimal dietary feedback and general healthy-eating brochures. Internet education was provided via an innovative Mediterranean Eating Website. Dietary changes were assessed with 7 d estimated food diaries at baseline and 6 months, and data were analysed to calculate the Mediterranean Diet Score, a composite score based on the consumption of eight components of the traditional Mediterranean diet. The 'intention-to-treat' analyses showed that, at 6 months, participants in the intervention group had significantly increased their intake of vegetables, fruits and legumes, as well as the MUFA:saturated fatty acid ratio in their diet, and had significantly increased plasma HDL-cholesterol levels and a reduced ratio of total:HDL-cholesterol. Participants in the control group increased their intake of legumes but showed no other favourable significant changes compared with baseline. This Internet-based, tailored-feedback intervention promoting components of the Mediterranean diet holds promise in encouraging a greater consumption of plant foods, as well as increasing monounsaturated fat and decreasing saturated fat in the Scottish diet; it also shows that the Mediterranean diet can be adopted by healthy individuals in northern European countries.