Inclusion Criteria:

- Adult patients, >/= 18 years of age

- Histologically confirmed CD20+ indolent non-Hodgkin's lymphoma according to WHO
classification system

- Patients must have received and must have relapsed or been refractory to one or more
lines of adequate therapy prior to enrolment, including at least one line consisting
of immunotherapy and/or chemotherapy and/or radiotherapy

- Eastern Cooperative Oncology Group (ECOG) performance status
Additional criteria for prolonged maintenance (Maintenance II):

- Completed MabThera/Rituxan-based Induction and initial 2-year maintenance
(Maintenance I) therapy with sc MabThera/Rituxan

- Partial response or complete response after Maintenance I

Exclusion Criteria:

- Transformation to high-grade lymphoma

- Aggressive lymphoma (e.g. mantle cell lymphoma)

- Presence or history of central nervous system (CNS) lymphomatous disease

- Other malignancy within 5 years prior to enrolment, except for curatively treated
carcinoma in situ of the cervix, squamous cell carcinoma of the skin or basal cell
skin cancer, or cervical carcinoma stage 1B or less, breast cancer in situ or
localized prostate cancer stage T1c if treated with curative intent and relapse- and
metastasis-free for at least 2 years prior to enrolment

- Inadequate hematological, hepatic or renal function

- Positive for HIV infection

- Active and/or severe infection (e.g. tuberculosis, sepsis and opportunistic
infections, active hepatitis B or C)

- Pregnant or breastfeeding women