Purpose: The primary purpose of this study was to measure the 16-year change in peak compensated static acoustic admittance (Peak Y[subscript tm]) in a population-based cohort of older adults, and to determine whether age was associated with any observed change in Peak Y[subscript tm]. Other tympanometric measures also were taken and analyzed. Method: Data from two examinations (1993-1995 and 2009-2010) of the population-based Epidemiology of Hearing Loss Study (n = 1,439 with data at both examinations, ages 48--84 years at baseline) were utilized to assess 16-year change. Tympanometric measures were taken using a 226-Hz probe tone, a positive-to-negative direction of pressure change, and a measured pump speed of 600/200 daPa/s. Results: During the 16-year period, Peak Y[subscript tm] declined an average of 0.009 mmho/year (0.009/year for women, 0.007/year for men). Among women, older baseline age was associated with greater decline in Peak Y[subscript tm]. Among men, baseline age was associated with change in Peak Y[subscript tm], but in a nonlinear pattern. Other tympanometric measures demonstrated little change after 16 years. Conclusions: These results demonstrate a small degree of middle-ear stiffening after 16 years among these older adults, but not enough to affect function in a manner that would influence clinical decisions.