This is a multicenter, Phase IIIb, randomized, double-blind, active-controlled, parallel-group, comparative study.

The objectives of this study are:

1. To compare the efficacy of tiotropium 18 mcg once daily plus Formoterol Fumarate Inhalation Solution (FFIS) 20 mcg twice daily to tiotropium 18 mcg once daily.
2. To obtain safety data on the use of tiotropium 18 mcg once daily plus FFIS 20 mcg twice daily compared to tiotropium 18 mcg once daily.

Inclusion Criteria:

• Medical diagnosis of COPD
• Current or prior history of cigarette smoking

Exclusion Criteria:

• Medical diagnosis of asthma
• Significant condition or disease other than COPD