OBJECTIVE To investigate the pharmacokinetics, safety and tolerability of aclidinium bromide 200 μg and 400 μg after a single dose and repeated once-daily doses in younger and elderly patients with moderate or severe chronic obstructive pulmonary disease (COPD). METHODS Younger (40-59 years; n = 12) and elderly (≥ 70 years; n = 12) patients were treated with aclidinium via the Genuair® inhaler. Patients received once-daily aclidinium 200 μg for 3 days; after a 7-day washout period, patients received once-daily aclidinium 400 μg for 3 days. Pharmacokinetic analyses were conducted on plasma and urine on Days 1 and 3 of both treatment periods. Safety and tolerability were assessed. RESULTS Aclidinium showed similar linear and time-independent pharmacokinetics in younger and elderly patients at each dose level and day of treatment. For both age groups at each dose level and day, aclidinium appeared rapidly in the plasma with a median tmax between 10 and 15 min; concentrations of aclidinium in the plasma declined rapidly with a t1/2 between 1 and 3 h. Plasma exposure with the 400 μg dose was ~ 2-fold higher than for the 200 μg dose in both age groups on both days. For both age groups, urinary excretion of aclidinium over 24 h was < 0.15% of the dose at each dose and day. Aclidinium 200 μg and 400 μg were safe and well tolerated in both age groups. CONCLUSION These data suggest that no dose adjustment of aclidinium is required when treating elderly patients with COPD.