Objective In this article, I examine how children's and parents’ immigration status (U.S. born, legal immigrant, or undocumented) is associated with children's access to insurance and healthcare and with children's physical health. Methods I use the first wave of the Los Angeles Family and Neighborhood Survey, which is representative of Los Angeles County in 2000–2001, to analyze data on parents' and children's immigration status, children's health insurance coverage, children's healthcare utilization, and children's health, using logistic and ordered logistic regression models. Results I find that undocumented immigrant children face severely constrained access to health insurance and a usual source of healthcare, while children with foreign‐born parents have lower global health status than children with U.S.‐born parents. Children with undocumented parents may have less access to a doctor diagnosis for common childhood ailments. Conclusion These results show that without being eligible for public insurance, many undocumented children lack health insurance and a usual healthcare provider, even in a part of the country with substantial experience serving immigrant families.