Background: CLL is the most prevalent form of adult leukemia. In recent years, there have been a number of newly approved therapies for the management of patients with CLL in both the 1^st line (1L) and relapsed/refractory settings, including ibrutinib (approved for 1L CLL, March 2016). Methods: USphysicians involved in CLL treatment decision-making were recruited into the Adelphi CLL Disease Specific Programme (February-May 2016). Physicians completed record forms on consecutively presenting patients > 18 years currently on active CLL treatment. Descriptive statistics analyzed demographics, clinical characteristics, and antineoplastic treatment patterns. Results: 700 patients diagnosed with CLL for an average of 3.0 years were captured. Patients’ mean age was 68.3 years, 53% were male, 75% were Caucasian, 25% had 17p deletion, and 55% were Medicare insured. Of the 81 physicians, 35% were based in an academic hospital setting, 51% in a non-academic hospital setting, 4% in both, and 9% were office-based. Within the overall cohort, BR was the most common 1L regimen (25%), while ibrutinib was the most common 2^nd line (2L) regimen (42%). Among patients with 17p deletion, BR was the most common 1L regimen (25%) and ibrutinib was the most common 2L regimen (50%). Older patients ( ≥ 65) were most likely to receive BR at 1L (28%), while 1L younger patients ( < 65) received FCR (24%). Conclusions: This analysis of real world treatment patterns identified BR, FCR, and ibrutinib as the most common 1L regimens in US CLL patients. Ibrutinib, BR, and idelalisib + rituximab were the most common 2L regimens. Choice of therapy varied depending on age and 17p deletion status. For example, FCR was more frequently used as 1L therapy in patients < 65 years, and the proportion of ibrutinib use as 1L therapy was higher in those with 17p deletion.