Objective: To investigate the epidemiology and associated factors of deciduous dental caries in 3-5 years old children in Henan Province, and to provide a epidemiological reference for prevention work of deciduous dental caries among children. Methods: According to the basic methods of the Fourth National Oral Health Survey, 12 kindergartens were randomly selected from 2 counties and 2 districts in Henan Province and a total of 1 296 children aged 3-5 years old were randomly selected with stratified multi-stage random sampling method. The deciduous teeth of these children were examined for caries and their guardians were surveyed with questionnaires regarding oral health behavior, knowledge and attitude. Results: Deciduous dental caries occurred in 755 children, accounting for 58.3% and the average decay-missing-filled teeth (dmft) was 2.83. The differences of prevalence of dental caries of boys and girls (60.5%, 56.0%) and mean dmft index (2.88, 2.78) were of no statistical significance(χ2/F=2.64, 0.22, P>0.05). The prevalence of dental caries and mean dmft index for 3, 4 and 5-year-old group was 46.7%, 2.02 and 60.9%, 2.85 and 67.5%, 3.64, respectively. There was statistical significance among three age groups(χ2/F=40.00, 21.68, P<0.01). No significant difference was found in the dental caries prevalence and mean dmft index between urban (58.9%, 2.87) and rural area (57.7%, 2.79)(χ2/F=0.20, 0.16, P>0.05). Multivariate logistic regression showed that age, feeding pattern within the first six months after birth, dental care experience and self-perceived oral health status associated with deciduous caries in 3-5 year-old children in Henan Province(P<0.05). Conclusion Dental caries prevalence is highly prevalent among preschool children in Henan Province. Effective caries precaution measures should be taken to improve oral health level of these children.