evidence: However, the prevalence increased by 43% from 2.21% (95% CI, 1.25%-3.17%) to 3.16% (95% CI, 2.50%-3.81%) in non-Hispanic Black individuals (P = .07 for trend), and by 40% from 1.49% (95% CI, 1.10%-1.87%) to 2.08% (95% CI, 1.09%-3.07%) in Hispanic individuals (P = .08 for trend). An increasing prevalence in non-Hispanic Black individuals was observed in the younger age group (3.02; 95% CI, 2.33-3.70 among those aged 3-11 years vs 2.60; 95% CI, 1.99-3.21 among those aged 12-17 years). [...] The decreasing trend in the prevalence of ASD between 2016 and 2018, especially the plateau in non-Hispanic White individuals, may suggest a stabilization of the environmental factors. The racial/ethnic disparities in ASD are complex and reflect multiple levels of inequities. These inequities range from individual etiologic factors (eg, genetic factors) and nonetiologic factors (eg, disease awareness and access to ASD evaluation)5 to environmental etiologic factors (eg, preterm birth and social experience in infancy). The main limitation of this study was the ascertainment of ASD cases, which was based on household respondents’ self-reports, rather than physicians’ evaluations. Further analysis to explore the racial/ethnic disparities by educational level, family income, and health insurance is necessary. [...] MMWR Surveill Summ. 2016;65(3):1-23. doi: