IMPORTANCE Current US immigration policy targets immigrants from Mexico and other Latin American countries; anti-immigration rhetoric has possible implications for the US-born children of immigrant parents. OBJECTIVE To assess whether concerns about immigration policy are associated with worse mental and physical health among US citizen children of Latino immigrants. DESIGN, SETTING, AND PARTICIPANTS This study of cohort data from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS), a long-term study of Mexican farmworker families in the Salinas Valley region of California, included a sample of US-born adolescents (n = 397) with at least 1 immigrant parent. These adolescents underwent a health assessment before the 2016 presidential election (at age 14 years) and in the first year after the election (at age 16 years). Data were analyzed from March 23, 2018, to February 14, 2019. EXPOSURES Adolescents aged 16 years self-reported their concern about immigration policy using 2 subscales (Threat to Family and Children's Vulnerability) of the Perceived Immigration Policy Effects Scale (PIPES) instrument. MAIN OUTCOMES AND MEASURES Resting systolic blood pressure, diastolic blood pressure, and mean arterial pressure; body mass index; maternal-and self-reported depression and anxiety problems (using Behavioral Assessment System for Children, 2nd edition); self-reported sleep quality (using Pittsburgh Sleep Quality Index [PSQI]); and maternal rating of child's overall health. All measures except sleep quality were assessed at both the aged-14-years and aged-16-years visits. Health outcomes at age 16 years and the change in outcomes between ages 14 and 16 years were examined among youth participants who reported low or moderate PIPES scores vs high PIPES scores. RESULTS In the sample of 397 US-born Latino adolescents (207 [52.1%] female) and primarily Mexican American individuals, nearly half of the youth participants worried at least sometimes about the personal consequences of the US immigration policy (n = 178 [44.8%]), family separation because of deportation (177 [44.6%]), and being reported to the immigration office (164 [41.3%]). Those with high compared with low or moderate PIPES scores had higher self-reported mean anxiety T scores (5.43; 95% CI, 2.64-8.23), higher maternally reported anxiety T scores (2.98; 95% CI, 0.53-5.44), and worse PSQI scores (0.98; 95% CI, 0.36-1.59). Youth participants with high PIPES scores reported statistically significantly increased levels of anxiety over the 2 visits (adjusted mean difference-indifferences, 2.91; 95% CI, 0.20-5.61) and not significantly increased levels of depression (adjusted mean difference-indifferences , 2.63; 95% CI,-0.28 to 5.54). CONCLUSIONS AND RELEVANCE Fear and worry about the personal consequences of current US immigration policy and rhetoric appear to be associated with higher anxiety levels, sleep problems, and blood pressure changes among US-born Latino adolescents; anxiety significantly increased after the 2016 presiden...