Blood-borne viral infections are widespread among injecting drug users; however, it is difficult to include these patients in serological surveys. Therefore, we developed a national surveillance program based on postmortem testing of persons whose deaths were drug related. Blood collected at autopsy was tested for anti-HBc, anti-HBs, anti-hepatitis C virus (HCV), or anti-human immunodeficiency virus (HIV) antibodies using commercial kits. Subsets of seropositive samples were screened for viral genomes using sensitive in-house and commercial polymerase chain reaction (PCR) assays. Hepatitis B virus (HBV) DNA was detected in 20% (3/15) of anti-HBc-positive/anti-HBs-negative samples, HCV RNA was found in 64% (16/25) of anti-HCV-positive samples, and HIV RNA was detected in 40% (6/15) of anti-HIV-positive samples. The postmortem and antemortem prevalences of HBV DNA and HCV RNA were similar. Postmortem HIV RNA testing was less sensitive than antemortem testing. Thus, postmortem PCR analysis for HBV and HBC infection is feasible and relevant for demonstrating ongoing infections at death or for transmission analysis during outbreaks.