We investigated the relationship of three phenotypic markers of atopy (allergy skin test reactivity, serum IgE level, and eosinophilia) to the prevalence of respiratory symptoms in 1,071 middle-aged and older men participating in the Normative Aging Study. Participants had all been health screened at the onset of the study in the 1960s to exclude individuals with asthma or other chronic respiratory diseases. Respiratory symptoms were grouped into three categories: asthma (adult onset) and other wheezing syndromes; cough and phlegm production; and hay fever. Multivariate logistic regression models were utilized to assess the independent relationship of each phenotypic marker to symptom prevalence adjusted for age, cigarette smoking, and the competing influence of the other markers. In this population, the prevalence of each symptom increased with serum total IgE concentration, this relationship being strongest for asthma. Skin test positivity (greater than or equal to 5 mm induration to one or more aeroallergens) was strongly associated with hay fever but was not significantly associated with symptoms of wheeze or cough and phlegm. Eosinophilia was associated with asthma and with phlegm production. The association of eosinophilia with phlegm production was present in skin test-negative as well as skin test-positive subjects and remained significant even after current smokers and individuals with asthma or hay fever were excluded. These data support the concept that asthma and hay fever are related to different immunologic host factors as reflected by expression of atopy phenotypes. Future investigations of immunologic factors in respiratory disease susceptibility should include, at a minimum, an assessment of all three phenotypic markers of atopy.