CONTEXT: Type 2 diabetes mellitus (T2DM) patients are at increased risk of cognitive impairment and dementia compared to healthy individuals. Lifestyle practices such as yoga can have a vital role in preventing and managing T2DM. Some studies have found that yoga can positively impact cognitive function in T2DM. OBJECTIVE: The study aimed to investigate the benefits of short-term yoga practice on heart rate variability (HRV) and cognitive function for T2DM patients, without a matched control group, to address the paucity of data on the effectiveness of yoga practice on cognitive health on T2DM individuals. DESIGN: Current study is a single group pre post design. SETTING: The study took place in the Department of Yoga and Life Sciences at Swami Vivekananda Yoga Anusandhana Samsthana (S-VYASA) in Bangalore, India. PARTICIPANTS: Participants were 21 T2DM patients from various hospitals, clinics and community setups, in different parts of Bengaluru city in India. INTERVENTION: The participants took part in one month of yoga practice. OUTCOME MEASURES: The research team used the Madrid card sorting test (MCST) to assess participants\' executive function (EF) at baseline and postintervention. In addition, the team monitored participants\' heart rate variability (HRV) in a resting phase and during task performance. RESULTS: Between baseline and postintervention: (1) participants\' reaction time for the MCST decreased for overall task performance (P = .01) and during rule shifting (P = .03); (2) a significant reduction occurred in participants\' random errors (REs) and incorrect responses, at P = .02 for both, whereas a significant increase occurred in correct responses and efficient errors (EEs), at P = .03 and P = .01, respectively; (3) the low frequency (LF) and LF/high frequency (HF ) ratio for the HRV decreased; HF increased but the difference wasn\'t statistically significant; and (4) a statistically significant decrease occurred in LF and LF/HF and an increase in HF occurred during task performance. CONCLUSION: Yoga therapy had beneficial effects on cognitive performance for the T2DM participants. The yoga practice also positively affected autonomic functions during task performance and suggesting that it can reduce task-induced stress. It\'s important for the future studies to validate the current findings with a randomized controlled trial.