Backgrounds.- Bipolar disorder in teenagers has been very difficult to diagnose, commonly related to the shared symptomatology with ADHD. Neuropsychological deficit related to fronto- temporal disorder have been described. Objectives. To describe neuropsychological disturbances in euthymic bipolar adolescents and clinical differences between BD+ADHD subjects vs. Only BD adolescents. Methods. Seventeen bipolar teenagers were included, whose informed consents were previously collected. BPRS, Beck’s depression schedule, ADHD severity scale, K-SADS-PL and Kiddie mania scales were used. During euthymia London Tower, Wisconsin WISC and WAIS were applied. Results. BPD I was diagnosed in 23.4% of cases, BPD II in 35.3%, and BPD NOS in 35.3%. The ADHD comorbidity was diagnosed in 82.4% of cases. The group with BD + ADHD showed a higher prevalence for other psychiatric comorbidities in comparison with BD only group, mainly anxiety disorders, conduct disorders and substance abuse disorders. In euthymia the most common neuropsychological disorders were visospatial perception failure, practical judgment, and social paradigm resolution. We found higher impairments in verbal fluency in BD+ADHD group. Conclusions. We conclude that even during euthymia right fronto- temporal disorders were found. Research regarding neuropsychologial performance in bipolar teenagers is important for their future use as a biomarker for early diagnosis.