The Medicaid program, authorized by federal legislation in 1965, provides health care access to low-income persons who are age 65 or over, blind, disabled, or members of families with dependent children. Since that time, legislative options and mandates have expanded the categories of eligibility to include Medicaid coverage for children and pregnant women in poverty, refugees, and children in state care. The Missouri Medicaid program is jointly financed by the federal government and Missouri State Government, and is administered by the State of Missouri. The agency charged with administration of the Medicaid program is the MO HealthNet Division, a division within the Department of Social Services.

Missouri’s commitment to providing health care for the indigent predates the federal enabling legislation. In 1959, a limited medical assistance program began. Coverage was limited to inpatient hospital care with a maximum reimbursement rate of $5.00 per day. Benefits were limited to 100 days per patient per year. In 1963, due to opportunities afforded by federal law, Missouri implemented limited prescription drug and dental programs for the adult assistance categories. At that time, these were the only programs for which federal funds could be claimed.

In October 1967, the 74th Missouri General Assembly enacted legislation establishing a medical services program under the provision of Title XIX of the Social Security Act. The program established was the Missouri Medicaid program. When Missouri’s Title XIX, or "Medicaid" program was implemented, the new services covered by the program included outpatient hospital care, physicians' services, and professional nursing home care. Implementation also provided first time coverage to the blind; permanently and totally disabled recipients; and greatly expanded services to Aid to Families with Dependent Children.

The state also has a limited medical assistance program, which is funded with General Revenue and Blind Pension funds. The program allows Child Welfare Services (CWS) recipients and Blind Pension recipients who are not eligible for the federal Medicaid program to receive necessary medical care.

The Personal Responsibility Work Opportunity Reconciliation Act of 1996 (PRWORA) was signed into law on August 22, 1996. (PL 104-193)

The bill was a comprehensive piece of legislation that created Temporary Assistance for Needy Families (TANF), which replaced the entitlement program of Aid to Families with Dependent Children (AFDC). This legislation severed the automatic link between eligibility for cash assistance and the receipt of Medicaid. Families may continue to be eligible for Medicaid through Medical Assistance for Families (MAF), but Medicaid eligibility is no longer guaranteed for those families receiving cash assistance.

On September 1, 2005, the 93rd Missouri General Assembly enacted legislation that reduced optional Medicaid services provided to adults, unless the individual is receiving benefits under a category of assistance for pregnant women or the blind.

The amount appropriated for Medicaid programs in State FY-1968 was $19.4 million. In comparison, the State FY-2008 budget appropriation was $5.5 billion.

With passage of the Missouri Health Improvement Act of 2007 (SB 577) by Missouri’s 94th General Assembly session, the medical assistance program on behalf of needy persons, Title XIX, Public Law 89-97, 1965 amendments to the federal Social Security Act, 42U.S.C. Section 301 et seq., shall be known in the state of Missouri as MO HealthNet. In addition to Medicaid being referred to as MO HealthNet the title “Division of Medical Services” is now referred to as “MO HealthNet Division”. This change became effective September 1, 2007.