Inclusion Criteria:

1. Understand and voluntarily sign an informed consent form.

2. Age >/= 18 years at the time of signing the informed consent form. (Revlimid has not
been tested in younger patients)

3. Able to adhere to the study visit schedule and other protocol requirements.

4. Diagnosis of relapsed/refractory AML (other than APL) or high-risk MDS (IPSS
categories intermediate-2 and high) with chromosome 5 abnormality as a sole
abnormality or with additional abnormalities. MDS patients with blast percentage of
>/= 10% will be considered high-risk.

5. All non-hematological toxicity of previous cancer therapy should have resolved to grade1 (except alopecia or other toxicities not involving major organs).

6. Should not have received any prior treatment for AML or MDS within 2 weeks of
starting Revlimid. Use of hydrea to control proliferative disease will be allowed
prior to starting Revlimid and for 7 days during cycles 1 and 2 (Maximum daily dose
of 7gm).

7. Eastern Cooperative Oncology Group (ECOG) performance status of
8. Laboratory test results within these ranges: • Serum creatinine bilirubin aminotransferase (ALT or SGPT) related to disease

9. Females of childbearing potential (FCBP) must have a negative serum or urine
pregnancy test with a sensitivity of at least 50 milli-International unit (mIU)/mL
within 10 - 14 days prior to and again within 24 hours of prescribing Revlimid
(prescriptions must be filled within 7 days) and must either commit to continued
abstinence from heterosexual intercourse or begin TWO acceptable methods of birth
control, one highly effective method and one additional effective method AT THE SAME
TIME, at least 4 weeks before she starts taking Revlimid. FCBP must also agree to
ongoing pregnancy testing.

10. (continued from above) Men must agree to use a latex condom during sexual contact
with a FCBP even if they have had a successful vasectomy.

11. All study participants must be registered into the mandatory RevAssist® program, and
be willing and able to comply with the requirements of RevAssist®.

12. Disease free of prior malignancies for >/ = 2 years with exception of currently
treated basal cell, squamous cell carcinoma of the skin, or carcinoma "insitu" of the
cervix or breast.

Exclusion Criteria:

1. Any serious medical condition, laboratory abnormality, or psychiatric illness that
would prevent the subject from signing the informed consent form.

2. Pregnant or breast feeding females. (Lactating females must agree not to breast feed
while taking Revlimid).

3. Any condition, including the presence of laboratory abnormalities, which places the
subject at unacceptable risk if he/she were to participate in the study or confounds
the ability to interpret data from the study.

4. Use of any other experimental drug or experimental therapy within 28 days of
baseline.

5. Known hypersensitivity to thalidomide.

6. The development of erythema nodosum if characterized by a desquamating rash while
taking thalidomide or similar drugs.

7. Any prior use of Revlimid.

8. Concurrent use of other anti-cancer agents or treatments. (Use of hydrea permitted as
indicated in inclusion criterion 6)

9. Known positive for HIV or infectious hepatitis type B or C.

10. Heart rate less than or equal to 50.