Diabetes is the seventh leading cause of death in the United States. For most patients, medication alone is not sufficient to achieve glycemic control; attention must also be paid to multiple healthy behaviors including diet, regular physical activity, and stress management. Yoga, a mindfulness practice with emphasis on relaxation, meditation, and deep breathing, may have special relevance to people with type 2 diabetes mellitus (T2DM). Yoga practice may positively affect stress and other self-care tasks that will contribute to improved glycemic control. The Healthy, Active, and in Control (HA1C) study is designed to examine the feasibility and acceptability of yoga among adult patients with T2DM. In this pilot randomized controlled trial, adults with T2DM were randomly assigned to either a 12-week Iyengar Yoga intervention given twice weekly, or a twice-weekly 12-week program of traditional exercise (e.g., walking, stationary cycling). Assessments are conducted at the end of treatment (12 weeks) and at 3 and 6 months postintervention. The HA1C study will assess feasibility and acceptability (e.g., attendance/retention rates, satisfaction with program), glycemic outcomes (e.g., HbA1c, fasting blood glucose, postprandial blood glucose), and changes in physiological (e.g., salivary cortisol) and behavioral factors (e.g., physical activity, diet) relevant to the management of T2DM. Focus groups are conducted at the end of the intervention to explore participants' experience with the program and their perception of the potential utility of yoga for diabetes management.