Introduction: Despite advances in the oral health of children in recent decades, early childhood caries continues to pose a serious threat to childhood welfare. This study assessed the prevalence of and risk factors for Early Childhood Caries (ECC) in children 12- to 36- month-old in Greater Cairo and evaluated the impacts of ECC on their quality of life. Materials and Methods: The target population for this cross-sectional study included 12- to 60-month-olds (n =603) attending random nurseries across Greater Cairo and their parent. The parents were given a structured questionnaire covering areas regarding personal information, child medical history, feeding and dietary habits of the child, parental dental attitudes and behaviors, and quality of life of children. In addition, the last section of the questionnaire was answered by the nursery’s caregiver to assess her dental knowledge, attitudes and her feeding practices when the child is under her care. Children were examined to determine their dmft and intensity of ECC index. An educational pamphlet was handed out at the end of the study to all the participants. It gave out a comprehensive set of recommendations for the prevention of ECC. Results: The results showed that the prevalence of ECC and S-ECC were rather high, 31% and 25.9%, respectively, with an overall prevalence of 56.9%. Mean intensity of ECC was 0.10+ 0.15 and mean dmft was 1.97+ 3.02. Nearly all of the decayed primary teeth were untreated. Nursery level was a significant predictor of ECC occurrence; children from low level nurseries were more prone to develop ECC than their peers. Other factors shown by regression analysis to be important predictors were child’s age, snack type, time to visit the dentist, caries prevalence in the parents and feeling pain at time of the examination. However, higher rank children from low level nurseries (p=0.01) from large families (p=0.019) with lowest family income (p=0.0011), low mothers’ education levels (p=0.023), house wife mothers (p=0.001) who relied on demand breastfeeding (p=0.001) or bottle feeding (p=0.015) mainly had higher prevalence, intensity and dmft scores of ECC, and they all came from low level nurseries. Significant predictors of ECC were nursery level, child’s age, snack type, time to visit the dentist, caries prevalence in the parents and feeling pain at time of the examination. Parental educaon (p=0.001, 0.023), income (p=0.011), number of children (p=0.019), child order (p=0.001), male gender (p=<0.001) had a significant association with ECC especially in low level nurseries. Children who started brushing later (p=0.005), went to the dentist only when had pain (p<0.001), never visited the dentist before (p=0.02), had parents who had caries in their teeth (p< 0.001), and had higher frequency of snacking had more dental caries. Parents who reported the need to visit the dentist only when in pain showed an increased rate of caries in their children. Quality of life (p=0.001) was significantly reduced in those children with higher prevalence of ECC and this affected many areas in their daily lives. As for the nursery’s caregiver, the oral hygiene practices (p=0.001) done for children under her care proved a significant difference, though her attitude did not. Finally, children’s’ diet in the nursery, both brought from home(p=0.001) and given by the nursery(p=0.04) was an important determinant of caries in these preschoolers. Conclusion: This study demonstrated ECC to be rather high among preschool children in greater Cairo region representing a serious problem affecting their quality of life. It is recommended to increase knowledge of parents about proper feeding habits and oral health practices as these, among other numerous factors, are responsible for this increased prevalence of ECC.