Educational Testing Service has developed an alternate form of the Navy Officer Classification Battery, and an additional form of the Mechanical Comprehension Test of this battery. Test questions were tried out at the U.S. Naval School, Officer Candidate, at Newport. Item difficulty and item discrimination indices were then derived, and constituted an important element in the process of selecting items for use in the alternate forms of the tests. Standardization of the tests was carried out by ETS with the further cooperation of the Officer Candidate School. As a final step in the project, conversion tables were prepared linking raw scores on each test to raw scores on the previous test form and to the Navy Standard Score scale. Correlational and other statistical data obtained during the standardization indicated that a satisfactory alternate form of the battery and a satisfactory additional form of the Mechanical Comprehension Test had been prepared.