Inclusion Criteria:

1. Males and females age 6 to 18 years of age
2. Parent or legal representative must have a level of understanding sufficient to communicate intelligently with the investigator and study coordinator, and to cooperate with all tests and examinations required by the protocol.
3. Patients and their legal representative must be considered reliable.
4. Each patient and his/her authorized legal representative must understand the nature of the study. The patient's authorized legal representative must sign an informed consent document.
5. Patient must have a diagnosis of bipolar I or bipolar II disorder and currently displaying an acute manic, hypomanic, or mixed episode (with or without psychotic features) according to the DSM-IV based on clinical assessment and confirmed by structured diagnostic interview (Kidd Schedule of Affective Disorders).
6. Patients must have an initial score on the Y-MRS total score of at least 15.
7. Patient must be able to participate in mandatory blood draws.
8. Patient must be able to swallow pills.

Exclusion Criteria:

1. Patients with chronic medical illness, DSM-IV substance dependence within the past 6 months, pregnant or nursing females, and those at serious risk of suicide will be excluded from the study
2. investigator and his/her immediate family; defined as the investigator's spouse, parent, child, grandparent, or grandchild.
3. Serious unstable illness including hepatic, renal, gastroenterologic, respiratory, cardiovascular (including ischemic heart disease), endocrinologic, neurologic, immunologic, or hematologic disease.
4. Known history of QT prolongation (ie. Congenital long QT syndrome), cardiac arrhythmia, recent myocardial infarction, or heart failure
5. Concurrent medications known to prolong the QT interval including: antiarrhythmics (quinidine), antimicrobials and antimalarials (erythromycin, clarithromycin, ketoconazole, sparfloxacin, moxifloxacin, levofloxacin, gatifloxacin, chloroquine) and antihistamines (diphenhydramine, hydroxyzine).
6. Known hypokalemia or hypomagnesemia
7. Uncorrected hypothyroidism or hyperthyroidism
8. History of severe allergies or multiple adverse drug reactions
9. Non-febrile seizures without a clear and resolved etiology
10. Leukopenia or history of leucopenia without a clear and resolved etiology
11. DSM-IV substance (except nicotine or caffeine) dependence within the past 6 months
12. Judged clinically to be at serious suicidal risk
13. Any other concomitant medication with primarily central nervous system activity other than specified in Concomitant Medication portion of the protocol
14. History of intolerance of Ziprasidone as determined by the principal investigator.
15. Treatment with an irreversible monoamine oxidase inhibitor within 2 weeks prior to visit 2
16. Current diagnosis of schizophrenia
17. For concomitant stimulant therapy used to treat ADHD, patients must have been on a stable dose of medication for 1 month prior to randomization