Abstract Adenovirus infections are frequent events but they do not usually cluster in distinct epidemics and are therefore somewhat inconspicuous. In the immunocompetent host they are rarely associated with severe illness or mortality. Syndromes commonly associated with adenovirus infection include respiratory illness, ranging from the common cold to pneumonia, (kerato)conjunctivitis and diarrhoea. On the basis of 21 publications, the frequency of occurrence of enteric adenoviruses 40 (Ad40) and Ad41 in stool specimens from immunocompetent children with diarrhoea and controls was evaluated in the perspective of other enteric pathogens. The median observed (all studies) and mean control-corrected (controlled studies) frequencies were 4.0% and 2.9% for enteric adenovirus, 3.4% and 0% for non-enteric adenovirus, 21% and 19% for rotavirus, 15% and 11% for calicivirus, 6.7% and 7.9% for astrovirus and 14% and 17% for nonviral microorganisms, respectively. An interesting epidemiological observation was the gradual change in the predominance among enteric adenoviruses from Ad40 in the early 1980s to Ad41 in the late 1980s, which occurred first in Australia and the Netherlands, later in Canada and lastly in Japan. More serious illness is caused by adenovirus infections in immunocompromized individuals. In 19 studies involving bone marrow transplant recipients with intestinal disease, on average 4.4% of the stool samples contained an adenovirus. A median percentage of 12% of the recipients contracted an adenovirus infection of any organ, 17% of whom died as a possible or probable result of this infection. There are indications that these rates are rising.