The objective of this study is to evaluate the long-term safety and tolerability of ABT-089 in children with ADHD.

Inclusion Criteria:

• The subject was randomized into Base Study (M06-888 or M10-345) and completed the Treatment Period.
• If female, subject must be practicing at least one method of birth control throughout the study.
• If female, the result of a pregnancy test is negative.
• The subject is judged to be in generally good health.

Exclusion Criteria:

• The subject experienced a serious adverse event in Base Study (M06-888 or M10-345) that the investigator considered "possibly" or "probably related" to study drug.
• The subject has taken any ADHD medication between the last dose of study drug in Study M06-888 or M10-345 and the first dose of study drug in the current study.
• The subject has a positive urine drug screen for alcohol or drugs of abuse.
• The subject anticipates a move outside the geographic area.