Criteria are presented for vocational evaluators who use work samples as one means of determining the vocational potential of blind clients. Included are rationale for the use of work samples; specific steps for their administration, scoring, and use of norms; and criteria for modifying present work samples and developing new ones. A literature review documents the need for work evaluation services for the blind. It covers jobs currently held by the blind and predictions for future employment trends, problems in achieving competitive employment, and current evaluation techniques, both psychological tests and work samples. An evaluation plan for a blind client outlines skills and worker characteristics which should be observed and recorded. Administration of work samples for several specific purposes is examined. The section on modification in administration procedures is organized like the Materials Development Center's "Suggested Format and Content of a Work Sample Manual" (Thomas, 1973) so that evaluators can follow modification which may need to be made in currently used work sample manuals which follow that format. Principles and modifications discussed are applied to three commercial work sample batteries in common use: Jewish Employment and Vocational Service Work Sample Battery, Singer Vocational Evaluation System, and Valpar Component Work Sample Series. Charts on each battery provide modifications in instructions or materials suggested when using the work sample with a visually impaired client. (JT)