Inclusion Criteria:

- Diagnosis of Myelodysplastic Syndrome by FAB. Can be made with cytogenetic analysis
of Bone Marrow or Hematologist evaluation

- Patient must have had bone marrow biopsy and aspiration to confirm diagnosis within
60 days prior to treatment

- ECOG performance status of 0-2

- An EKG must be performed within 7 days prior to treatment to confirm QT interval
<460msec.

- Serum creatinine less than or equal to 2.5 times the upper limit of normal.

- Serum bilirubin less than or equal to 2.5 times the upper limit of normal.

- Serum potassium greater than or equal to 4.0 mEq/dL and serum magnesium greater than
or equal to 1.8 mg/dL. If these serum electrolytes are below the specified limits on
the baseline laboratory tests, electrolytes should be administered to bring the serum
concentrations to these levels before administering arsenic trioxide.

- Patients must be 18 years of age to participate in this study

Exclusion Criteria:

- Pregnant or nursing women, and men or women of childbearing potential who are
unwilling to employ adequate contraception.

- Corrected QT interval of greater than or equal to 460msec in the presence of serum
potassium and magnesium values within normal range.

- Significant CHF, coronary is ischemia or serious Arrhythmias including conduction
delays.

- Peripheral neuropathy greater than or equal to 2.

- Evidence of active infection

- Concurrent treatment with maintenance therapy, cytotoxic chemotherapy, radiation, or
investigational agents.

- Inability or unwillingness to comply with the treatment protocol, follow up, or
research tests.