Immune activation is a hallmark of human immunodeficiency virus type 1 (HIV-1) infection and impacts innate and adaptive immunity. Individuals coinfected with HIV-1 and hepatitis C virus (HCV) may have increased immune activation early in HIV disease because of a high HCV antigen load in tissues such as the liver. We evaluated T cell markers of activation and maturation in women with or without HIV-1 infection, by HCV antibody and HCV RNA status. We found increased percentages of activated CD8(+) T cells (i.e., CD8(+)HLA-DR(+)38(+) cells and CD8(+)CD28(+)HLA-DR(+) cells) but not of CD4(+) T cells among women who tested positive for HIV-1, HCV antibody, and HCV RNA, compared with HIV-1-positive women who tested negative for HCV antibody. Because CD8(+) T cell activation is related to HIV-1 disease progression, these data may have implications for the medical management of patients coinfected with HIV-1 and HCV.