The objective of this work was to design a test to measure the degree of knowledge on food and nutrition in school-age children from elementary first and second grades. A graphic instrument was designed according to the psychological child development and was based on the specific objectives pursued by the curriculum programs of the Ministry of Education. The test was developed around the following topics through 15 items: Area 1: Basic Concepts on Food and Nutrition (9 items) and Area 2: Food, Personal and Environmental Hygiene (9 items). The test was pilot tested on 103 school-age children of both grades (1:1), of both sexes (1:1), belonging to Peñalolén and Las Condes counties from Chile's Metropolitan Region and from high and low socioeconomic status (SES) (1:1), measured through the Graffar's Modified Method. The final version of the test was applied in a representative sample of 1.482 school-age children from Chile's Metropolitan Region from elementary first and second grades during 1986-1987. Content validity was assured by a team of judges and by the curriculum programs. Reliability was assessed by the Spearman correlation with the Spearman-Brown correction. Item-test consistency was determined by the Pearson correlation coefficient. Data were processed by the statistical analysis system (SAS) package. Results showed that reliability coefficient was 0.84 and item-test consistency was equal or above 0.25 in all items. It can be concluded that this test can be useful to determine the degree of knowledge on food and nutrition at the onset of elementary school, both in Chile and in other countries.