INTRODUCTION: it is necessary to develop an instrument that enables identifying unhealthy eating habits, and to know those erroneous concepts that the adult population may have in relation to sugary products to be able to design and implement appropriate nutritional education strategies for this population sector. AIM: to perform the content validation of a questionnaire to determine the level of knowledge, perception, and habits of sugary product consumption in the adult population through expert judgement. METHODS: it is a content and psychometric validation study, carried out between September and October of the last year, in which 13 experts participated, who assessed each one of the instrument's items. Fleiss' kappa coefficient was used with the aim of measuring the degree of agreement. A pre-test was performed with 237 participants to measure the degree of comprehensibility of the instrument. RESULTS: the strength of agreement reached for the dimensions of knowledge and opinion regarding sugary product consumption was almost perfect, and substantial for behaviour with respect to said products. The strength of agreement fluctuated between moderate and almost perfect for each pair of experts. The characteristics of sufficiency and relevance obtained the highest scores using Fleiss' according to the degree of overall agreement between experts. The new version of the questionnaire achieved a high degree of comprehensibility. CONCLUSIONS: the results suggest that the instrument is valid and can be applied in future studies to evaluate knowledge, perceptions and habits about sugary products in the adult population, thus contributing to the prevention of chronic diseases and the promotion of a better quality of life.