The three dimensional stress distribution in a thin cylindrical pressure vessel with hemispherical end caps is determined experimentally. The three dimensional photoelastic technique of stress freezing was used. The use of symmetry of stresses in simplifying the usually cumbersome procedure of three dimensional photoelastic analysis is illustrated. A complete procedure of casting the model from epoxy and subsequent curing is presented. The problems encountered during casting, curing, machining and cementing of the model are given and their remedies discussed. Particular attention is given to the machining problems encountered during this investigation. The experimental results are compared with linear and non-linear theoretical solutions. Poor agreement between the experimental results and the theoretical solutions is discussed. Recommendations for improving the experimental accuracy have been made.