Complex chronic lifestyle disorders are the leading causes of death and disability worldwide. Stress and anxiety associated with today's hectic life schedule and polluted environment have contributed a lot in triggering and causing many chronic diseases and decreased quality of life, even with pharmacologic treatment. Most of the chronic complex diseases, such as chronic obstructive pulmonary disease, depression, autoimmune diseases, cancer, cardiovascular diseases, obesity, and diabetes mellitus share underlying mechanisms like high levels of stress, anxiety, depression, oxidative stress, shorter telomeres, persistent activation of hypothalamo-pituitary adrenal axis, inflammation and dysregulated immune system, and thus need to be managed by an integrated approach that targets both mind and body. The individuals with these conditions have been reported to benefit from yoga, but the underlying mechanism of action of yoga remains unclear. The aim of this chapter is to summarize the mechanism of action underlying the cumulative effect of yoga on multiple pathways at a cellular level.