Five methods were evaluated for the detection of adenovirus directly from nasopharyngeal aspirates (NPA), including conventional and rapid virus culture, two antigen detection tests, and the polymerase chain reaction (PCR). NPA specimens were obtained from 269 military conscripts suffering from an acute respiratory infection during an adenovirus outbreak. In 133 cases, paired blood specimens were also available. Virus culture followed by a hexon-specific immunofluorescence revealed 159 (59%) adenovirus-positive specimens and it was used as a reference method. In comparison to conventional culture, a rapid 2-day culture method had a sensitivity of 71%. The sensitivities of an enzyme immunoassay and time-resolved fluoroimmunoassay were 53% and 46%, respectively. The PCR method employing Ad7 hexon-specific primers showed a high sensitivity of 94%, and revealed an additional 15 (6%) specimens that could not be confirmed by virus culture. Serology based on significant adenovirus antibody rises had a diagnostic efficacy nearly equal to the virus culture and PCR methods, but a relatively high number of discordant results was found. The present study demonstrates that PCR is a very sensitive rapid diagnostic method for detecting adenovirus specific DNA in NPA specimens of adults.