Attention deficit hyperactivity disorder (ADHD) and mania show a broad overlap of symptoms and a high comorbidity. This situation moots questions about common neurobiological and pathological mechanisms and treatments. We report efficacy of additional methylphenidate treatment in a patient with bipolar disorder and ADHD comorbidity. A 32-year-old married man. He was admitted to outpatient clinic with complaints of inability to control his behaviors, inattention, hyperactivity and mood variability. His first psychiatric admission was ten years ago. He discontinued treatment because of lack of benefit. He had depressive episodes in 2006 and 2007, after than he was diagnosed with bipolar disorder. Mood stabilizer treatment was started in 2007. He experienced hypomanic and depressive episodes for 3-4 times, but he did not receive a regular treatment. In the mental examination at the time of hospitalization, his affect was observed as elevated and showed signs of mania. Young mania scale score was 10; Wender-Utah test result was compatible with the diagnosis. He was treated with valproic acid and quetiapine, initially. As he did not show improvement by means of attention deficits in the follow-up period, methylphenidate has been added on actual treatment. Patient has got significant benefit from treatment. Many symptoms of ADHD and mania share some pathogenetic routes. There is a consensus that stimulants should be used carefully in mania. This case indicated that stimulant can be use full in comorbid states and there is not much risk in the presence of mood stabilizers and close follow up.