We studied rhinovirus-associated illnesses from 1976 to 1981 among residents of the community of Tecumseh, Michigan, in a continuation of similar studies done in 1966-1971. Rhinoviruses were the most frequently isolated respiratory pathogen in all age groups, including young children. The pattern of age-specific isolation rates was similar to that for total respiratory illness. Rhinovirus-associated illnesses were generally mild but of relatively long duration; restriction of daily activity was frequent, especially in certain age groups. Typing of all isolates has been completed; with high-quality antisera nearly all isolates could be typed. Thus, new serotypes are probably not evolving, and most have already been identified. Differences in frequency of occurrences of different serotypes were evident, but ranking in order of importance was difficult based on existing data.