In this paper, the experimental results of a full scale test on a 372, 700 DWT oil tanker are reported of the structural behavior under statically loaded conditions. Extensive measurements are made on the deformations of the ship's hull and the transverse ring in addition to the stress distributions at totally 595 measuring points, including deck and bottom transverses, vertical webs and struts, swash bulkhead, horizontal girders and vertical stiffeners on the transverse bulkhead in cargo oil tank. Local stress measurements are also made on the slots of the web of bottom transverses. Also described is a comparison of the test results with the theoretical findings by the structural analysis, in which used are several computer programmes based on the finite element method for three-dimensional frame works, plane members and shell structures, that have been developed by Nippon Kaiji Kyokai and Ishikawajima-Harima Heavy Industries Co., Ltd. It is concluded from this investigation that the deformations of the transverse rings and the relative deflections of wing tanks as well as the stress distributions in the above-mentioned structural components of oil tankers can be well predicted by these computer programmes within a satisfactory accuracy for practical design purpose.