Purpose: No nationwide oral health survey has previously been carried out in Jordan. The aims of the study were to assess the burden of dental caries and gingival health among children aged 6 and 12 years in relation to sociodemographic factors and to ascertain the trend over time in the occurrence of caries and the need for dental care. Materials and Methods: A cross-sectional epidemiological survey was carried out which included 2496 children aged 6 years and 2560 children aged 12 years selected by stratified cluster sampling. Children were examined in schools and data comprised information about caries and gingival health status. WHO methodology and criteria were applied. Structured questionnaires were used to collect information about oral hygiene, dental visits, consumption of sugars and parents' level of education. Results: The caries prevalence rates were 76.4% in 6-year-olds and 45.5% in 12-year-olds, and caries experience was 3.3 dmft and 1.1 DMFT, respectively. The prevalence of caries varied significantly by sex and geographical region. In both age groups, children of the social low and middle groups had significantly higher levels of caries experience, more untreated decayed teeth and fewer filled teeth than did children of the upper socioeconomic group. Multivariate regression analysis showed that social class was the most important independent variable for caries. The results from 2005 were compared with similar data collected in the capital, Amman, in 1993. For all social classes, the mean caries experience and the amount of untreated dental caries increased over time. Moreover, 17.7% of 6-year-old children and 49.1% of the 12-year-olds had gingival bleeding. Significant differences in gingival health were found by sex, location, geographical areas and socioeconomic group. Conclusion: Oral disease is a significant public health problem in Jordan. Strengthening of the school oral health programme is needed for effective prevention and control of caries and promoting gingival health. A systematic school oral health programme including oral health promotion should be established. Palabras clave: dental caries, gingival health, Jordan, social inequality, trends in dental caries