Due to the shared risk factors for viral transmission, coinfection of human immunodeficiency virus and hepatitis C virus is common. This study examined the seroprevalence of hepatitis C virus among human immunodeficiency virus–infected patients in inpatient and outpatient settings. A retrospective chart review of 256 human immunodeficiency virus–infected patients was conducted in Prince George's Hospital Center (inpatients from 1 September 2011 to 1 March 2012) and Glenridge Medical Center (outpatients from 1 January 2011 to 31 December 2012). The mean age of the population was 46 ± 12 and 44 ± 11 for inpatients and outpatients, respectively. Human immunodeficiency virus–infected men comprised 61.9% inpatients and 64.8% outpatients. The overall prevalence of hepatitis C virus infection in human immunodeficiency virus/AIDS patients was 12.5% (32/256), with a higher prevalence in inpatient group than that in outpatient group (24.6% vs 11.2%, p < 0.01). The percentages of drug abuser (43.8% vs 16.5%, p < 0.01) and alcoholism (25.0% and 14.3%, p < 0.05) in hepatitis C virus / human immunodeficiency virus–coinfected patients were higher than those in human immunodeficiency virus–monoinfected patients. In addition, only 64.9% of human immunodeficiency virus–infected and 50.0% of hepatitis C virus / human immunodeficiency virus–coinfected inpatients were followed up with outside care after discharge. To our knowledge, this study, for the first time, revealed that hepatitis C virus / human immunodeficiency virus coinfection was significantly higher in inpatients compared to outpatients. Considering its high prevalence and comorbidities associated with hepatitis C virus / human immunodeficiency virus coinfection, it is highly recommended that evaluation of hepatic damage, especially fibrosis, should be carefully initiated during hospitalization as well as outpatient care.