Inclusion Criteria:

1. Patients with B-cell CLL with indications for treatment by National Cancer Institute
(NCI) Working Group Criteria, or Rai Stage III or IV or patients with CLL requiring
treatment because of any of the following: disease related symptoms, progressive
marrow failure (development or worsening of anemia and/or patients' thrombocytopenia)
progressive splenomegaly, progressive lymphoadenopathy, progressive lymphocytosis

2. Patients who have received a minimum of one prior purine analog-based chemotherapy
regimen. Prior treatment with corticosteroids, immunotherapy, monoclonal antibody or
radiation therapy is permitted. All previous cancer therapy, including radiation,
hormonal therapy and surgery must have been discontinued 2 weeks prior to treatment
in this study. Any cytotoxic chemotherapy must be discontinued 4 weeks prior to
treatment in this study.

3. Age more or equal to 18 years (CLL is not observed in patients less than 18 years of
age).

4. Eastern Cooperative Oncology Group (ECOG)/World Health Organization (WHO) performance
status 0-2.

5. Adequate renal function indicated by serum creatinine less or equal to 2 and adequate
hepatic function indicated as total bilirubin less or equal to 2 times the upper
limit of normal.

6. Understand and sign Informed Consent after the investigational nature, study design,
risks and benefits of the study have been explained.

7. Females of childbearing potential (FCBP)must have a negative serum or urine pregnancy
test with a sensitivity of at least 50 mIU/mL within 10 - 14 days prior to and again
within 24 hours of starting lenalidomide 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 lenalidomide. FCBP must also agree to
ongoing pregnancy testing.

8. Continued from #7. Men must agree to use a condom during sexual contact with a female
of child bearing potential even if they have had a successful vasectomy. All patients
must be counseled at a minimum of every 28 days about pregnancy precautions and risks
of fetal exposure.

9. Continued from #8. A female of childbearing potential is a sexually mature woman who:
1) has not undergone a hysterectomy or bilateral oophorectomy; or 2) has not been
naturally postmenopausal for at least 24 consecutive months (i.e., has had menses at
any time in the preceding 24 consecutive months).

10. Disease free of prior malignancies for 5 years with exception of currently treated
basal cell, squamous cell carcinoma of the skin, or carcinoma "in situ" of the cervix
or breast. Patients with malignancies with indolent behavior such as prostate cancer
treated with radiation can be enrolled in the study as long as they have a reasonable
expectation to have been cured with treatment modality received.

Exclusion Criteria:

1. Known sensitivity to thalidomide or its derivatives

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

3. Prior use of lenalidomide

4. Concurrent use of other chemotherapy agents.

5. Known positivity for Human immunodeficiency virus (HIV) or infectious hepatitis type
A, B or C.

6. Pregnant or lactating females.

7. A serious medical condition, laboratory abnormality or psychiatric illness that would
pose the subject at unacceptable risk if he/she were to participate in the study or
that would interfere with the ability of the patient to carry out the treatment
program or confine the ability to interpret the data from the study.

8. Documented prolymphocytic leukemia (prolymphocytes more than 55% in the blood).

9. Active cardiovascular disease as defined by the New York Heart Association class 3 or
4.