We are currently conducting a randomized, controlled trial (RCT) to evaluate the effectiveness of a telephone-delivered, nurse-administered, behavioral intervention among community patients with poorly-controlled diabetes and comorbid hypertension. This intervention is designed to simultaneously improve patient self-management of both blood glucose and BP. In order to establish the effectiveness of this intervention in a broadly generalizable population, this RCT takes place in a community primary care setting. We describe the design and design considerations of conducting this RCT in a community primary care setting, and provide baseline characteristics of the study sample.