A total of 65 ambulatory subjects over the age of 65 yr were studied to determine if mild impairment in cognitive function precludes reliable spirometric measures in the aged. Standardized questionnaires were used to obtain information on demographics, cigarette smoking, respiratory symptoms, and physician-diagnosed lung disease. Each subject performed several simple standardized tasks of cognitive function and underwent spirometric testing. A total of 36 women and 29 men participated. The mean age for the group was 74.9 +/- 5.6 yr; most were nonsmokers (never smokers, n = 28; former smokers, n = 29; and current smokers, n = 8). Of the 65 participants, 8 (12.3%) individuals were unable to perform at least three ATS-acceptable FVC maneuvers after suitable demonstration. These subjects were similar to the 57 subjects able to perform three acceptable maneuvers, except for worse scores on both the symbol-digit modalities test (23.3 +/- 3.6 versus 31.6 +/- 10.5, p < 0.001) and the trail-making test, Part B (244.3 +/- 87.1 versus 160.4 +/- 71.8, p < 0.01). Of the 57 subjects able to perform spirometry, 18 (31.6%) failed to meet ATS reproducibility criteria for FEV1, FVC, or both. Cognitive impairment was not associated with the ability to achieve reproducible measures. These results suggest that the vast majority of older subjects can perform reliable spirometry; those elderly unable to perform spirometry may have impairment in cognitive function requiring further evaluation.