Inclusion Criteria:

1. 18 to 70 years of age.
2. Patients with CD20 + CLL, mantle cell and follicular lymphoma who are eligible for allogeneic transplantation.
3. Patients with relapsed diffuse large B-cell lymphoma may be included if there were not eligible for autologous transplantation.
4. A fully-matched sibling donor.
5. Left ventricular EF > 40% with no uncontrolled arrythmias or symptomatic heart disease.
6. FEV1, FVC and DLCO > 40%.
7. Serum creatinine < 1.6 mg/dL. Serum bilirubin < 3X upper limit of normal.
8. SGPT < 3X upper limit of normal.
9. Voluntary signed, written IRB-approved informed consent before performance of any study-related procedure not part of normal medical care, with the understanding that consent may be withdrawn by the subject at any time without prejudice to future medical care.
10. Men and women of reproductive potential must agree to follow accepted birth control methods for the duration of the study. Female subject is either post-menopausal or surgically sterilized or willing to use an acceptable method of birth control (i.e., a hormonal contraceptive, intra-uterine device, diaphragm with spermicide, condom with spermicide, or abstinence) for the duration of the study. Male subject agrees to use an acceptable method for contraception for the duration of the study.

Exclusion Criteria:

1. Patient with active CNS disease.
2. Pregnant (Positive Beta HCG test in a woman with child bearing potential defined as not post-menopausal for 12 months or no previous surgical sterilization) or currently breast-feeding. Pregnancy testing is not required for post-menopausal or surgically sterilized women.
3. Known infection with HIV, HTLV-I, Hepatitis B, or Hepatitis C.
4. Patients with other malignancies diagnosed within 2 years prior to Study Day-13 (except skin squamous or basal cell carcinoma).
5. Active uncontrolled bacterial, viral or fungal infections.
6. History of Stroke within 6 months.
7. Myocardial infarction within the past 6 months prior to Study Day 1, or has New York Heart Association (NYHA) Class III or IV heart failure or arrythmias, unstable angina, uncontrolled congestive heart failure or arrythmias, or electrocardiographic evidence of acute ischemia or active conduction system abnormalities. Prior to study entry, any ECG abnormality at screening must be documented by investigator as not medically relevant.
8. A prior allogeneic transplant.
9. Serious medical or psychiatric illness likely to interfere with participation in this clinical study.
10. Patient has received other investigational drugs within 3 weeks before enrollment.
11. Hypersensitivity to bendamustine.
12. Prior known refractoriness to bendamustine.