Rationale: In senior subjects, static lung volumes are interpreted using prediction equations derived from primarily younger adult populations. Objectives: To provide reference equations for static lung volumes for European adults aged 65-85 and to compare the predicted values of this sample with those from other studies including middle-aged adults. Furthermore, we compare the lung volumes by plethysmography and helium dilution in senior subjects. Methods: Reference equations were derived from a randomly selected sample from the general population of 321 healthy never-smoker subjects aged 65–85 yrs. Spirometry and lung volume determinations by plethysmography and multibreath helium equilibration method were performed following the American Thoracic Society/European Respiratory Society recommendations. Reference values and lower and upper limits of normal were derived using a piecewise polynomial model. Measurements and Main Results: Plethysmography provided higher values than the dilutional method for all lung volumes, with wide limits of agreement. In addition to height, our reference equations confirm the age- and body size-dependence of lung volumes in older subjects. Practically all the estimations performed by extrapolating reference equations of middle-aged adults overpredicted the true lung volumes of our healthy elderly volunteers. Middle-aged reference equations classify as being below the TLC lower limit of normal between 17.9-62.5% of the females and 12.5-42.2% of the males of the current study. Conclusions: These results underscore the importance of using prediction equations appropriate to the origin, age and height characteristics of the subjects being studied.