Background: Despite significant improvements in children's oral health status over the past decades, dental caries still remains a major oral health problem, especially among socioeconomically deprived groups (Petersen 2003, WHO2003). The oral health program significantly affects the prevalence of caries and various risk factors for caries development. Oral health education program (OHE) has a positive effect on oral health behavior of children and oral health knowledge, (Petersen et al, 2004). Methods: This study was conducted in the school nursery classes of Greater Cairo to assess the prevalence of dental caries in preschool children, and to determine the influence of implementing an oral health education program (OHE) using illustrating posters and a cartoon film on the oral health status of children. The study involved a dental examination of children, a questionnaire about diet and hygiene habits that was filled before and after the program. Also the diseased children response to referral and the received dental services was assessed at the end of program. Results: A total of 1000 children participated: their mean age from 3 to 5 years old. 50.3% of the examined children had dental caries. There was a statistically significant correlation between age and dmf for the study age group, the higher age category shows higher dmf value. The results showed a significant positive effect of the oral health education program since more children in both poster and video groups adopted regular oral health behavior such as proper tooth brushing and healthy dietary habits. Among the children who were referred to dental treatment only 34% went to the dentist while 66% didn't go to the dentist. Causes of not visiting the dentist were mainly because the children didn’t complain from dental pain(39.7%) or due to they had primary teeth and will shed(40%), lesser number reported it due to fear from infection (8.3%), and high costs(7.4%). A few percentages were due to time, and history of bad experience. Most of the referred children went to private clinics which showed higher percentage of fillings and extraction+ fillings while governmental treatment showed higher percentage of extractions, giving medications and instructions. Conclusions: The study revealed high dental caries prevalence of preschool children in Greater Cairo. The oral health education program is an efficient method in modifying the dietary and oral hygiene habits and improving the oral health status during follow up periods. No difference was found between the poster and video groups in improving children oral-health status during follow up periods. There is a little awareness about importance of visiting dentists and restorations of primary teeth. Children's parents preferred to receive treatment at private clinics where conservative treatment was offered more than extraction on contrast to government clinics where the extraction was the most common treatment.