Specific suggestions and guidelines are presented for modifying psychological tests so that they can be used to obtain results that are not distorted by the individual's handicap. Focus is on testing persons with sight, hearing, and academic problems with the indication that principles developed for this fairly high percentage of the severely disabled population are applicable to other handicapped persons. Part I suggests methods of communicating instructions and items to the client in a way that he will understand what is required of him. Conditions of blindness, deafness, and mental retardation are defined and general test modification suggestions made for each. Part II contains examples of how specific tests can be modified to meet the special needs of the disabled and examples of commonly used tests that can be used without modifications with one or more of the three disability groups. A test review outline is presented followed by twenty-one individual test reviews under the following headings: achievement batteries and reading tests, character and personality, intelligence, vocations--clerical, vocations--dexterity, vocations--mechanical, and vocations--interests. Part 3 briefly describes a few tests designed for the severely disabled. (JT)