Objective: To evaluate the nutritional quality of products advertised on television (TV) during children's viewing time in Spain, applying the UK nutrient profile model (UKNPM). Design: We recorded 80 h of four general TV station broadcasts during children's viewing time in May and June 2008, and identified all advertisements for foods and beverages. Nutritional information was obtained from the product labels or websites and from food composition tables. Each product was classified as healthy (e.g. gazpacho, a vegetable juice) or less healthy (e.g. potato crisp snacks) according to the UKNPM criteria. Setting: Four free-of-charge TV channels in Spain: two national channels and two regional ones. Subjects: TV commercials of food and beverages. Results: A total of 486 commercials were broadcast for ninety-six different products, with a mean frequency of 5?1 advertisements per product. Some 61?5 % of the ninety-six products were less healthy, and the percentage was higher for foods (74?1 %). All (100 %) of the breakfast cereals and 80 % of the non-alcoholic drinks and soft drinks were less healthy. Of the total sample of commercials, 59?7 % were for less healthy products, a percentage that rose to 71?2 % during children's reinforced protection viewing time. Conclusions: Over half the commercials were for less healthy products, a proportion that rose to over two-thirds during the hours of special protection for children. This suggests that applying the UKNPM to regulate food advertising during this slot would entail the withdrawal of most food commercials in Spain. TV advertising of products with low nutritional quality should be restricted.