Inclusion Criteria:

- Diagnosis of acute myeloid leukemia (AML), meeting 1 of the following criteria:

- Relapsed AML in the following categories:

- Good-risk cytogenetics [inv(16), t (8;21)] in second relapse or in first
relapse following a remission of < 12 months

- Acute promyelocytic leukemia (M3) in second relapse or greater AND must
have relapsed following both tretinoin-anthracycline-based therapy and
arsenic trioxide-based therapy

- All other relapsed patients are eligible

- Untreated AML in the following categories:

- At least 65 years of age

- Myelodysplastic syndromes-AML (AML with trilineage dysplasia)

- AML with del5Q or monosomy 5, monosomy 7, or complex cytogenetics (≥ 3
cytogenetic abnormalities)

- Refused or ineligible for potentially curative options such as allogeneic stem cell
transplantation

- No clinical evidence of CNS or pulmonary leukostasis, disseminated intravascular
coagulation, or CNS leukemia

- ECOG performance status (PS) 0-2 or Karnofsky PS ≥ 60%

- Life expectancy ≥ 3 months

- Bilirubin normal unless attributed to hemolysis or Gilbert's disease in the opinion
of the investigator

- AST/ALT ≤ 2.5 times upper limit of normal (ULN)

- Creatinine normal OR creatinine clearance ≥ 60 mL/min

- No history of allergic reactions attributed to compounds of similar chemical or
biologic composition to vorinostat

- No uncontrolled intercurrent illness, including any of the following:

- Ongoing or active infection

- Symptomatic congestive heart failure

- Unstable angina pectoris

- Cardiac arrhythmia

- Psychiatric illness or social situation that would limit compliance with study
requirements

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- No known HIV positivity

- More than 4 weeks since prior radiotherapy

- More than 2 weeks since prior valproic acid

- More than 3 weeks since other prior treatment for AML, including hematopoietic growth
factors

- Hydroxyurea for WBC > 30,000/mm^3 allowed

- Recovered from prior therapy

- No concurrent filgrastim (G-CSF), sargramostim (GM-CSF), epoetin alfa, or darbepoetin
alfa

- No other concurrent investigational agents

- No other concurrent anticancer agents or therapies for this cancer