Abstract Background: Public health campaigns are focused on promoting increased vegetable and fruit (VF) consumption due to their association with health. Although the number of suggested portions is generally known to children in the UK, knowledge of what counts and what doesn't count as a portion of these foods is not clear.  We aimed to develop and test a succinct intervention about what constitutes a portion of VF. Methods: A succinct (45min.) teaching intervention regarding VF portion sizes; including pre- and post evaluations though a structured questionnaire, demonstrations with real-life models and hands-on examination of portions, oral communications and active engagement in the form of entertainment, was carried out with boys and girls (7-9 years, n=80) in various primary schools in Leeds. Activities included a question and answer session and individual and group competitions to confirm acquired knowledge. Results: Initial knowledge was acceptable, with 85% of them being aware of the UK recommendations from the 5-a-day program. Knowledge of portion sizes was minimal with only 2% of the participants being able to correctly identify the corresponding portion sizes of apples, juice, grapes, peas and broccoli. The acquired knowledge from the teaching intervention was statistically significant (p=.000). Previous knowledge was higher among girls (86% vs. 84% respectively) and acquired knowledge among boys (93% vs. 88% respectively) although gender differences were not significant. Conclusions: A succinct teaching intervention might be a feasible way to increase knowledge of VF portion sizes among primary school aged children.