PURPOSE In the United States, children who have a usual source of care (USC) have better access to health care than those who do not, but little is known about how parental USC affects children's access. We examined the association between child and parent USC patterns and children's access to health care services. METHODS We undertook a secondary analysis of nationally representative, cross-sectional data from children participating in the 2002-2007 Medical Expenditure Panel Survey (n = 56,302). We assessed 10 outcome measures: insurance coverage gaps, no doctor visits in the past year, less than yearly dental visits, unmet medical and prescription needs, delayed care, problems getting care, and unmet preventive counseling needs regarding healthy eating, regular exercise, car safety devices, and bicycle helmets. RESULTS Among children, 78.6% had a USC and at least 1 parent with a USC, whereas 12.4% had a USC but no parent USC. Children with a USC but no parent USC had a higher likelihood of several unmet needs, including an insurance coverage gap (adjusted risk ratio [aRR] 1.33; 95% confidence interval [CI], 1.21-1.47), an unmet medical or prescription need (aRR 1.70; 95% CI 1.09-2.65), and no yearly dental visits (aRR 1.12; 95% CI 1.06-1.18), compared with children with a USC whose parent(s) had a USC. CONCLUSIONS Among children with a USC, having no parent USC was associated with a higher likelihood of reporting unmet needs when compared with children whose parent(s) had a USC. Policy reforms should ensure access to a USC for all family members.