Objectives: To estimate the prevalence of confirmed and borderline subclinical chronic rheumatic heart disease (CRHD) through school-based screening in New Caledonia; to reassess the prevalence of acute rheumatic fever (ARF) and CRHD; and to identify the sociodemographic risk factors associated with confirmed and borderline CRHD in this population. Methods: A two-stage ultrasound screening, first at school and then with a cardiologist, was offered to all fourth-grade students (n=4,156). The sample was adjusted to account for those not screened during the initial examination. Prevalences were adjusted for the age of the population, ranging from 6 to 12.5 years, and risk factors were identified using multivariate logistic regression. Results: This screening established prevalences of confirmed and borderline subclinical CRC of 0.4% (95% CI: 0.2–0.6) and 0.7% (0.4–0.9), respectively, for a total prevalence of detected subclinical CRC of 1.1% (0.8–1.4). The New Caledonian registry for colorectal cancer and colorectal cancer had previously detected only 0.3% (0.2–0.5) of colorectal cancers in this population based on the clinical manifestation of colorectal cancer. This result allows for an upward adjustment of two-thirds in the prevalences of CRC (1.1% and 0.3%) and RAA (1.6%, 95% CI: 1.2–2.0) in this population. The risk of developing confirmed or borderline CRC increases significantly with age. Children of Melanesian ethnicity appear to have an increased risk of developing confirmed CRC compared to children of other ethnic origins. Conclusion: New Caledonia remains an endemic territory for AAR and CRC. This study identifies no other variable, apart from age, to explain the occurrence of confirmed or borderline CRC. Nevertheless, it raises the issue of ethnicity, particularly Melanesian ethnicity, in establishing a sociodemographic profile at risk for the occurrence of confirmed CRC. (R.A.)