Evaluate the effect of oral health educational program on the oral health knowledge, attitude and practice as well as oral hygiene condition of two groups of preschool children in both Port-Said and Jeddah nurseries (assessed over six months) using:1-Dental caries indices; DMFT, def (for mixed dentition) and dmft (for primary dentition).2-Oral hygiene index simplified OHI-s. A total number of 340 children (3-5.5 years) were included in this study. Children were classified into two main equal groups; Group A: Port Said preschool children (170 children) and Group B: Jeddah preschool children (170 children). Clinical examination was carried out to assess the child’s caries experience following WHO, 1997 criteria for diagnosis. It was conducted in schools’ nurseries under natural day light, while the children were sitting on ordinary chair facing a window. Dental examination was carried out using plastic disposable mouth mirror and dental explorer. A questionnaire and program were designed to measure knowledge, attitude and practice (KAP) for all the children. The questionnaire was read and explained to the children and their teachers and then recorded by the researcher after questioning the children. The dental health education program was based on educating the children the importance, frequency of teeth brushing in addition to the correct dietary habits and the value of healthy food using posters hanged on the walls, videos presented on LCD TV screen. Dental Model with a tooth brush was used to teach the children how to brush their teeth. At the end of the program children were given educational coloring mini posters and were prized by tooth pastes and brushes to encourage them maintain proper oral hygiene habits and dietary habits. According to the circumstances of the current study, we can conclude that there was no statistically significant difference between mean caries indices and OHI-s in the two groups either before or after the program. The program was effective in increasing the number of preschool children who knew the importance of their teeth and those who would prefer to treat their carious rather than extract them as well as increasing the number of children who brush their teeth. It was also effective in increasing awareness and attitude of preschool children toward eating healthy non cariogenic sandwiches and snacks as well as eating fruits and vegetables more frequently. On the other hand, the program was not effective in improving the oral hygiene index of the children and the frequency of teeth brushing.