The purpose of the study was to find out the efficacy of yoga therapy on selected bio-chemical variables among diabetic mellitus middle aged men. To facilitate the study, 30 subjects were selected at random from Virudhunagar district only. Their age were ranged between 40-60 years old. They were assigned into two groups as yoga therapy group and control group. All the subjects were tested prior to and immediately after the 8 weeks treatment in progression to bio-chemical variables such as blood glucose, high density lipoprotein (HDL) and low density lipoprotein (LDL). The initial and final scores in selected bio-chemical variables were put in-to statistical treatment using Analysis of Covariance (ANCOVA) to find out the significant mean differences. Results revealed that yoga therapy helped in increasing the level of HDL and decreasing the blood glucose and LDL level in blood and systematic eight weeks of yoga therapy reduced the blood glucose, LDL and increased the HDL more than the control group.