Maternal depression can have severe and lasting consequences for both a mother and her child. This brief uses the National Survey of Drug Use and Health to estimate the prevalence, severity, and treatment of major depression among low-income mothers with young children (ages 0-5). We find that one out of eleven low-income mothers with young children had a major depressive episode in the past year, and nearly one-third did not report receiving any treatment. While uninsured low-income mothers had much lower treatment rates than insured low-income mothers, rates were comparable across treatment providers, suggesting that Medicaid fills an important gap.