Inclusion Criteria:

- Confirmed diagnosis of CD20-positive CLL (per IWCLL guidelines, Hallek et al 2008)

- Previously untreated CLL requiring treatment according to the IWCLL guidelines
(Hallek et al 2008), as assessed by the investigator

- Adequate baseline bone marrow function unless it due to underlying CLL disease No
previous treatment for CLL by chemotherapy, radiotherapy, or immunotherapy

- Patients who are not appropriate to receive more intensive chemotherapy in the
judgment of the investigator

- Life expectancy of > 6 months

Exclusion Criteria:

- Treatment with any other investigational agent or participation in another clinical
trial within 28 days prior to the start of Cycle 1

- Transformation of CLL to aggressive B-cell malignancy History of severe allergic or
anaphylactic reactions to monoclonal antibody therapy

- Known hypersensitivity to chlorambucil or any of its excipients

- History of other malignancy that could affect compliance with the protocol or
interpretation of results Known active bacterial, viral, fungal, mycobacterial, or
other infection (excluding fungal infections of nail beds) or any major episode of
infection requiring treatment with IV antibiotics or hospitalization (related to the
completion of the course of antibiotics) within 4 weeks before the start of Cycle 1

- Major surgery (within 4 weeks prior to the start of Cycle 1), other than for
diagnosis

- Known infection with human immunodeficiency virus (HIV) or Human T-Cell Leukemia
Virus 1 (HTLV-1) seropositive status

- Positive hepatitis serology

- Women who are pregnant or lactating

- Fertile men or women of childbearing potential unless 1) surgically sterile or 2)
using an adequate measure of contraception such as oral contraceptives, intrauterine
device, or barrier method of contraception in conjunction with spermicidal jelly

- Effective contraception is required while receiving obinutuzumab. For women,
effective contraception is required to continue for >= 12 months after the last dose
of obinutuzumab. For men, effective contraception is required to continue for 6
months after the last dose of chlorambucil treatment.

- Vaccination with a live vaccine a minimum of 28 days prior to the start of Cycle 1