From 2000 to 2011, there were 808 and 2,738 incident cases of acute and chronic hepatitis C, respectively, among active component members of the U.S. Armed Forces; crude overall incidence rates during the period were 5.16 (acute hepatitis C) and 17.48 (chronic hepatitis C) per 100,000 person-years. Incidence rates of acute hepatitis C diagnoses steadily declined (by approximately 80 percent overall) during the period; rates of chronic hepatitis C diagnoses also declined but proportionately less overall than for acute hepatitis C. Declining trends likely reflect avoidance of risky behaviors, comprehensive screening of blood products, and accession standards that include screening for illicit drugs and antibodies to HIV-1.