To determine the prevalence of rotator cuff tears in asymptomatic shoulders we conducted a prospective clinical and ultrasonographic study of 411 volunteers. We anticipated an age-dependent outcome and divided the patients into 4 age-groups. Overall, we found evidence of a rotator cuff tear in 23% of the patients. In group 1 (aged 50 to 59 years), 13% (22 of 167) of the patients had tears; in group 2 (aged 60 to 69 years), 20% (22 of 108) of the patients had tears; in group 3 (aged 70 to 79 years), 31% (27 of 87) of the patients had tears; and in group 4 (age > 80 years), 51% (25 of 49) of the patients had tears. An astonishingly high rate of rotator cuff tears in patients with asymptomatic shoulders was thus demonstrated with increasing patient age. At this stage it remains unclear, however, which parameters convert an asymptomatic rotator cuff tear into a symptomatic tear. As a result, rotator cuff tears must to a certain extent be regarded as "normal" degenerative attrition, not necessarily causing pain and functional impairment.