Inclusion Criteria:

Patients with low to Int-1 risk MDS

1. ECOG performance status of < 2 at study entry (see Appendix II).

2. Disease free of prior malignancies for 5 years with exception of currently treated
basal cell, squamous cell carcinoma of the skin, or carcinoma "insitu" of the cervix
or breast.

3. Serum bilirubin levels < 1.5 times the upper limit of the normal range for the
laboratory (ULN). Higher levels are acceptable if these can be attributed to active
hemolysis or ineffective erythropoiesis.

4. Serum glutamic-oxaloacetic transaminase (SGOT) (aspartate aminotransferase [AST]) or
serum glutamic-pyruvic transaminase (SGPT) (alanine aminotransferase [ALT]) levels <
2 x ULN.

5. Serum creatinine levels 1.5 x ULN

6. Absolute neutrophil count > 1000/mm³

7. Platelet count > 30,000/mm³

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

9. Females of childbearing potential (FCBP)† must have a negative serum or urine

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® (lenalidomide).

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 therapy within 28 days of baseline.

5. Known hypersensitivity to lenalidomide, azacitidine, or mannitol.

6. Any prior use of Vidaza® (azacitidine).

7. Prior use of Revlimid® (lenalidomide) for more than 84 days (three 28 day cycles).

8. Concurrent use of other anti-cancer agents or treatments.

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