All results are based on an internal pressure of 1 psi and a mean sphere diameter of 1 inch; values for other pressures and sizes are obviously in direct proportion.This study was undertaken as part of a general investigation of the reinforcement of openings in pressure vessels by the Pressure Vessel Research Committee of the Welding Research Council.The intent was to obtain stress values for radial cylindrical outlets in spherical pressure vessels that could be compared with experimental results in the same field. If, as a result of this comparison, the theoretical data appear to be reasonably valid, they can then be used as a basis for the estimation of stress conditions in openings of this type, over the whole range of sizes and proportions currently employed in industry.