Chronic lymphocytic leukemia (CLL) is the most common leukemia in the Western world. Since in most cases CLL remains an incurable disease, the goals of therapy are to improve quality of life and to prolong survival. This study will evaluate the participant's related outcomes and experience of CLL in adult participants who are treated in the Spain.

Study participants will receive oral treatments for CLL as prescribed by their study doctor in accordance with approved local label. Adult participants prescribed various treatments will be enrolled. Around 132 participants will be enrolled in the study in sites in Spain.

Participants will receive oral treatments for CLL according to the approved local label. The overall study duration will be 18 months.

There is expected to be no additional burden for participants in this trial. All study visits will occur during routine clinical practice.

Inclusion Criteria:

• Have documented chronic lymphocytic leukemia (CLL) according to International Workshop on Chronic Lymphocytic Leukemia (iwCLL) criteria.
• Under oral treatment for CLL, either first-line or relapsed/refractory (R/R) therapy.
• Treatment for CLL started 9 months (+/- 4 weeks) before inclusion for first-line therapy or 21 months (+/- 4 weeks) before inclusion for R/R, under authorized conditions.
• In the opinion of the investigator, cognitive ability to understand and answer the questionnaires specified in the study protocol.
• Able to comply with the study protocol in the investigator's judgment.

Exclusion Criteria:

• Currently receiving any chemotherapy or chemoimmunotherapy.
• Transformation of CLL to aggressive non-Hodgkin's lymphoma (NHL) (Richter's transformation or pro-lymphocytic leukaemia).
• Currently participating in interventional research (not including non-interventional study, post-marketing observational study, or registry participation).
• Any serious medical condition or abnormality in clinical laboratory tests that, in the investigator's judgment, precludes the participant's safe participation in and completion of the study.

Adult participants diagnosed with chronic lymphocytic leukemia (CLL) treated with fixed-time duration (FTD) or continuous oral regimens who attend to a regular follow up visit at a Spanish participating hospital will be eligible to participate in the study.