Inclusion Criteria:

• All patients with histologically or cytologically confirmed Richter's transformation, prolymphocytic leukemia, aggressive, or relapsed/refractory B-cell chronic lymphocytic leukemia are eligible for this protocol.
• Patients must be 18 years of age or older.
• Patients must have a performance status of 0-2 (Zubrod scale).
• Patients must have adequate renal function (serum creatinine <= 2 mg/dL or creatinine clearance > 50 mL/min). Patients with renal dysfunction due to organ infiltration by disease may be eligible after discussion with the P.I. and consideration of appropriate dose adjustments.
• Patients must have adequate hepatic function (bilirubin <= 2 mg/dl; SGOT or SGPT < 2.5x the ULN for the reference lab unless due to leukemia or congenital hemolytic disorder [for bilirubin]). Patients with hepatic dysfunction due to organ infiltration by disease may be eligible after discussion with the P.I. and consideration of appropriate dose adjustments.
• Female patients of childbearing potential (including those < 1 year post-menopausal) and male patients must agree to use contraception.
• Patients must sign an informed consent indicating that they are aware of the investigational nature of this study.
• Patients must have platelet counts > 20,000, unless lower counts are due to disease involvement or autoimmune disorders.

Exclusion Criteria:

• Untreated or uncontrolled life-threatening infection.
• Oxaliplatin, fludarabine, cytarabine or rituximab intolerance.
• Pregnancy or lactation.
• Chemotherapy and/or radiation therapy within 4 weeks.
• Medical condition, including mental illness or substance abuse, deemed by the investigator to be likely to interfere with a patient's ability to sign informed consent, cooperate and participate in the study, or interfere with the interpretation of the results.