This paper deals with the real gas effects of the hypersonic flow over a cylinder with a blunt nose. The analysis is made using the Lighthill model of an ideal dissociating gas in equilibrium. The real gas effects on the high entropy layer adjacent to the body due to the curvature of the detached shock in front of the blunt nose have been evaluated for the cases Mx221E;=40 amp; Mx221E;=22 at different altitudes, using pure Oxygen as flowing media. The density profiles and the dissociation levels at various distances from the nose have been plotted. The proportion of Oxygen atoms remains considerable upto relative distances x/d =0(100) where d is the diameter of the nose base. It is found that a significant portion of the energy of the shock heated gas goes to dissociate the Oxygen molecules and the quantitative evaluation of this energy has been carried out
