The objective of this study was to assess the impact of an educational programme on both children's knowledge and behaviour towards the sun. The study included 282 children aged between 8 and 11 years in their third year of primary school coming from 13 schools in the Nantes area (located in the west of France). It was a two-arm opened control trial, with group A in which the children were taught by their teacher about their skin and sun protection, according to the programme called 'to live with the sun' and a control group (B) in which the children did not receive any educational programme about sun protection. Self-administrated questionnaires at the baseline, posttest and follow-up were used to assess knowledge and behaviour of the students. The data were paired to follow the evolution of each child and a knowledge score and a sun protection habits score were calculated. At the baseline there was no significant difference in knowledge and sun protection habits scores between the two groups. Six months after the educational prevention programme we observed a knowledge score significantly higher in group A (mean: 7.66) compared with group B (mean: 6.77) (P<0.00001), but concerning the sun protection habits score there was no significant difference between the two groups. The programme had a beneficial effect on the children's knowledge persisting for at least a few months but had no impact on their behaviour towards the sun.