Purpose: The purpose of this paper is to evaluate the effectiveness of a structured programme on handwashing which has taken into account of the developmental stage of children. Design/methodology/approach: This is a pilot study using a structured handwashing programme as intervention. The intervention group (n=15) receives the structured education programme on handwashing in addition to their existing curriculum, whereas the control group (n=15) receives only the teaching content of their curriculum. The programme contains five teaching sessions delivered on a weekly basis. Storytelling, health education, games, experiments, and hands-on activities are planned. Outcome evaluations include the knowledge level and behaviours on handwashing. The behaviour compliance over time is also assessed after the programme. Findings: After the education programme, the knowledge level of students in both groups increased, but significant improvement in handwashing practice is observed only in the intervention group. A noticeable improvement in the handwashing practice of the experimental group is seen immediately after the programme, but the children seem to have difficulties in maintaining the habit. Research limitations/implications: The small sample size may limit the external validity of findings to other preschool institutions. Future replications of the study are needed with larger, representative samples. Originality/value: The paper indicates that the knowledge and skills of proper handwashing of preschool children can be positively influenced by the use of a structured education programme. The results of the study suggest some implications for preschool educators, parents, and school health educators. (Contains 1 figure and 1 table.)