An instructional system design model was developed for training new employees of the American Express TRS (Travel Related Services) Company, Inc. on the Distributed Office Support System (DISOSS), an electronic mail system. The project used the Interservice Procedures for Instructional Systems Development, which consists of five phases: analysis, design, development, implementation, and evaluation. Needs analysis revealed that a training need existed. Information was obtained through observation, help desk calls, survey of existing clients, and consultation with subject matter experts. In designing relevant instruction, a task analysis was performed and measurable objectives for DISOSS instruction were identified. The development phase produced an instructional strategy that incorporated all objectives. Transparencies and handouts were produced, and appropriate media were selected. The DISOSS instruction was delivered twice within the implementation phase of the model; 21 participants from the target population received instruction. Formative evaluation consisted of one-on-one and small group trials. The summative evaluation used an entry behaviors test, pretest, posttest, and attitude questionnaires to measure reaction and learning. Learners improved significantly based on pre- and post-test scores. (Appendixes, amounting to almost two-thirds of the thesis, include instruments, task analysis, performance objectives and test items, instructional strategy, instructional materials, evaluation instruments and results, and 20 references.) (YLB)