OBJECTIVES: Chronic hepatitis C is a major public health problem whose incidence is expected to increase. But, treatments are available that can eliminate the virus in about 50% of cases. The purposes of this research were to: examine the prevalence in the Louisiana Medicaid population, determine testing rates and follow-up physician visits in at-risk populations and examine treatment of hepatitis C. METHODS: The was a retrospective analysis of Louisiana Medicaid medical and pharmacy claims. RESULTS: The 3-year prevalence of hepatitis C as determined by a primary or secondary diagnosis was 7.08 per 1000. Of those diagnosed from 1998-2000, 35% were age 41-50; 31%, age 21-40; and 23%, age 51-64. Of the 25,788 recipients who were tested for hepatitis C in the 3-year period, the highest testing rate in at-risk groups was among those with hepatitis B with almost 73% having had a hepatitis C test. Other at-risk groups were not tested at that rate. Of the 25,788 tested for hepatitis C, 17,385 received follow-up care (an outpatient physician visit within 90 days of the test). Of those who were tested, 643 received a diagnosis of hepatitis C with 489 (76%) receiving treatment. Of those treated, 364 (74.44%) started on monotherapy and 125 (25.56%) started on combination therapy. Switches from monotherapy to combination therapy were common. After 6 months, 132 had switched to combination therapy and 204 had switched by 12 months. Of those diagnosed with cirrhosis, 88.07% also had a diagnosis of hepatitis C. Of recipients with other advanced liver disease, 53.47% had a hepatitis C diagnosis. CONCLUSIONS: There is a high prevalence of hepatitis C in the Louisiana Medicaid program. Many at risk-recipients are not being tested. Of those tested, most received follow up care and most diagnosed with hepatitis C were receiving treatment.