Mothers have an important role to play in teaching their children about sexual issues and shaping children's sexual knowledge, attitudes and behaviours. In many cases, however, mothers themselves need help and support. This study was conducted to examine the effects of a sex education programme on the knowledge and attitudes of the mothers of pre-school children. Eighty mothers of pre-school children were randomly divided into an experimental and a control group. The experimental group received an education and training programme delivered over two 2-h sessions. The control group received no such intervention. Researcher-constructed knowledge and attitude questionnaires were completed by both groups before and one month after the intervention. Findings showed no significant differences between the two groups in terms of knowledge and attitudes before the training. After the education and training intervention, however, there was a significant increase in the mean score for both knowledge and attitudes in the experimental group compared to the control group. Study findings suggest that the sex education programme for the mothers of pre-school children can improve their knowledge and attitudes.