Data on autism spectrum disorders (ASD) in French Guiana are sparse and do not allow for a reliable estimate of their prevalence. However, such data are necessary for developing services that meet actual needs, particularly in the context of addressing the region’s structural shortcomings. The objective of this study was to estimate the prevalence of ASD among children aged 6 to 11 living in French Guiana, and to describe their main characteristics and care. Methods - The study’s methodology and inclusion criteria were modeled after those of the child disability registries in mainland France. Children with ASD were identified using medical records from the Departmental House for People with Disabilities (MDPH) or any facility diagnosing or supporting children with ASD in the region. Results - In 2016, 65 of the 74 children identified with ASD were included in the study. The prevalence was 18.4 per 10,000 children. This prevalence ranged from 3.4 to 33.8 per 10,000 children depending on the community of municipalities of residence (p<0.01). Although the rate of school enrollment and support was higher in 2017–2018 than at the time of diagnosis, medical and social services and professionals were insufficient to meet the needs. Conclusion - This study highlights a low prevalence of ASD compared to global estimates, particularly in the western part of the region at the start of the 3rd Autism Plan. Monitoring these data may help assess the local impact of public policies promoting early diagnosis and intervention, as well as plan for the necessary resources.