The proliferation of poor immigrant children in the United States raises concern about their high uninsurance rates and access to care. We examined the joint effects of health insurance status and place of birth on use of health services by children of the working poor. Of foreign-born children, 52 percent were uninsured and 66 percent had a regular care source, compared with 20 percent and 92 percent, respectively, of native-born children. Foreign-born uninsured children were less likely than their native-born peers were to have a regular care source or to have sought care. Health insurance and immigration policies must act in concert to increase health care access for foreign-born children.