Objective: To describe the process used to develop a medication choice decision aid (DA) for patients with type 2 diabetes. Methods: We developed the DA through active collaboration with patients, clinicians, and designers, direct observations of clinical encounters, literature review, and collaborative development of design criteria. Insights from these processes informed the iterative creation of prototypes that were reviewed and field tested in actual consultations. Results: The goal of the DA was to facilitate a conversation between the clinician and the patient about diabetes medication options. Four iterations of the DA were developed and field-tested before arriving at issue cards that organized the data for five medications around glucose control, hypoglycemia, weight changes, daily routine, self-monitoring and side effects. These cards successfully generated conversations during consultations. An ongoing clinical trial will determine if this DA affects patient adherence and outcomes. Conclusions: A collaboratively developed DA designed to create a conversation about diabetes medications may lead to more patient-centered treatment choices. Practice implications: If effective, this DA could replace disease-centered treatment algorithms for patient-centered conversations that enhance the management of patients with type 2 diabetes. © 2008 Elsevier Ireland Ltd. All rights reserved.