Various yogic practices focus on breathing. Breathing may affect brain waves. This cross-sectional study was conducted to see the effect slow and deep respiration on EEG activity in experienced Yoga practitioners at the Department of Physiology at AIIMS, Bhopal, India. The duration of the study was about one year. EEG was taken and was analyzed by Dinamika - Advanced Test System, Moscow, Russia. Paired t-test using graph pad software was used for statistical analysis. The Delta percentage decreased and the other wave's percentages theta, alpha, and beta increased significantly. The person becomes deeply relaxed and more focussed on slow and deep breathing.