Food choices of adolescents have become increasingly unhealthy, putting them at increased risk of malnutrition, as they grow older. The study investigated the determinants of food choices of adolescents in order to assess their nutritional knowledge and implication. World Health Organisation (WHO) describes children aged 10-19 years as adolescents. Four hundred and one adolescents who were in secondary schools were interviewed from six of the thirty local government areas of Osun State, which is a south-western state of Nigeria. Based on the population of secondary schools in the local government areas, thirty-two schools were sampled. Pre tested structured questionnaires using a set of high quality colour photographs of foods and drinks that would typically be offered to adolescents were used. The photographs, showing one item each, included foods such as biscuits, buns, meat pie that were classified as "snacks" and those, such as rice and beans garnished with vegetable and either fish/meat stew, stewed beans, pounded yam that formed part of a conventional meal. In the same manner, photographs showing a bottle of coke, milk, chocolate drink and home made non-alcoholic drinks were presented. This was used to elicit information from the respondents. Descriptive statistical techniques such as frequency counts, percentage, mean and standard deviation, likewise inferential tools, such as, correlation analysis and analysis of variance (ANOVA) were used in data analysis. The study showed positive and significant correlation between the preference and nutritional contents of foods (r = 0.514, p<0.05) and drinks (r = 0.346, p<0.05).