The aim of this study was to assess the effect of age on early reversibility testing (ERT) in patients with asthma. Forty-nine nonsmokers with asthma were investigated. In all cases, disease duration was less than 15 years; the absolute change (absolute variability, AV) in forced expiratory volume in I second (FEV1) on ERT was greater than 100 mL; and the increase in FEV1, on ERT was greater than 10%. Patients were categorized as group I (younger than 50 years; n = 24) and group 11 (50 years or older; n = 25). There were no significant differences between the groups regarding disease duration and severity. The mean patient ages in groups I and 11 were 40.3 +/- 7.9 years and 59.2 +/- 7.1 years, respectively, and the corresponding mean baseline FEV1 values were 62.2 +/- 23.7% and 67.4 +/- 21.1% of predicted value (p > 0.05). Pulmonary function tests were performed at baseline, and then repeated for ERT 20 minutes after inhalation of 200 mug salbutamol. After ERT, the respective findings for groups I and 11 were as follows: AV 412 +/- 184mL and 247 +/- 138mL; percentage change (PC) in FEV1 21.5 +/- 9.3% and 16.9 +/- 7.5%; and percent of predicted change (PPC) in FEV1 13.6 +/- 6.5% and 9.9 +/- 4.9%. The AV, PC, and PPC values for group I all were higher than the corresponding findings for group 11, and the differences in AV and PPC were statistically significant (p = 0.001, p < 0.05). The study showed that elderly asthma patients exhibit significantly lower AV and PPC after ERT. To improve the accuracy of asthma diagnosis in elderly patients, limits of ERT should be redefined.