OBJECTIVE: Patient preferences are crucial in treatment decision-making when several equally efficacious alternative treatments are available. The objective of this study was to investigate the principal drivers of treatment preference among individuals with type-2 diabetes. METHODS: We conducted 11 focus groups with 84 adults with type-2 diabetes supplemented with treatment preference driver checklists. RESULTS: The first 5 focus groups yielded 10 drivers of treatment preference. The second 6 focus groups ranked the importance of the 10 drivers among 100 points. The principal driver of treatment preference was medication effectiveness with an average score of 36.2 out of 100. The next two highly-rated drivers were treatment flexibility and physician recommendation (9.5 and 9.4, respectively), followed by quality of life impacts and correct dosing (7.5 each), financial costs (7.3), treatment convenience (6.4), physical side effects (6.3), emotional side effects (6.0), and treatment tolerability (3.8). A full 62% of participants chose 5 or more drivers, while only 12 % chose one or two drivers. We then asked participants to assume medication effectiveness was perfect and to reallocate the 100 points among the remaining 9 drivers. In this round, the principal driver of treatment preference was physical side effects (17.4). The next most highly-rated drivers were financial costs and physician recommendation (12.9 and 12.2, respectively), followed by correct dosing (11.1), treatment flexibility (10.9), quality of life impacts (10.1), treatment convenience (9.4), emotional side effects (8.5), and treatment tolerability (7.3). Only 8% of participants chose one or two drivers, while 38% chose eight or more drivers. CONCLUSIONS: Great variability exists in the drivers of treatment preference among individuals with type-2 diabetes. Group averages mask tremendous inter-individual variability in the importance of drivers and their relative rank. These findings underscore the need for continued methodological work on the concept of treatment preference.