Although HCV is more prevalent among people with severe mental illness (SMI; e.g., schizophrenia, bipolar disorder) than in the general population (17% vs 1%), no large previous studies have examined HCV screening in this population. In this cross-sectional study, we examined administrative data for 57 170 California Medicaid enrollees with SMI to identify prevalence and predictors of HCV screening from October 2010 through September 2011. Only 4.7% (2674 of 57 170) received HCV screening, with strongest predictors being nonpsychiatric health care utilization and comorbid substance abuse.