Background: The purpose of this research study was to identify factors that affect mental health care for children with special health care needs (CSHCN) and to identify how these factors vary among different socioeconomic levels. Methods: Data were obtained from the National Survey of Children with Special Health Care Needs, 2000-2002. The analysis examined the relationships of demographic characteristics, geographical location of household, severity of condition, and social factors on unmet need for mental health care. Multiple logistic regression models were constructed for four socioeconomic status (SES) levels defined by the federal poverty level (FPL): <133%; 133-199%; 200-299%; ≥300%. Standardised regression coefficients were calculated to compare among SES strata. Results: There were 38,866 CSHCNs represented in the survey with 9,639 needing mental health care in the past 12 months. The household income distribution was 22% below the 133% FPL, 15% between 133-199% FPL, 18% between 200-299% FPL, and 45% at or above 300% FPL. Black race, ethnicity, insurance type/status, geographical location of household, and number of kids in the household were significant in the <133% of FPL stratum for predicting having received all needed mental health care in the last 12 months. Age and geographical location of household were significant in the 133-199% of FPL stratum. Maternal education was significant in the 200-299% of FPL stratum. Severity of condition, other race, and insurance type/status were significant in the ≥300% of FPL stratum. Conclusions: Factors affecting unmet needs for mental health care differed by socioeconomic status. Future research should explore a more in-depth picture of the CSHCN population that includes stratification by income groups to better understand and serve this population. © 2009 Association for Child and Adolescent Mental Health.