This study examined the effects of a year-long word processing program on learners' holistic writing skills. Based on results of a writing pretest, 80 seventh grade students were designated as relatively high or low in prior writing achievement and assigned to one of two groups: a word processing treatment and a conventional writing process treatment. Students in each treatment produced two weekly writing assignments and four major papers over the course of one year. At the conclusion of the study, each was given a standardized writing test which was evaluated for structure and organization, correct use of the parts of speech, punctuation, capitalization, and spelling. Analysis consisted of a 2X2 completely crossed treatment by achievement factorial design, featuring two levels of treatment and two levels of prior achievement. Results indicate that relatively low achieving learners scored significantly better when using the word processing treatment than low learners in the conventional treatment; however, word processing was not effective for the relatively high ability students. Lack of this efficacy is attributable to two reported factors: difficulty in keyboarding and problems in accessing the microcomputers. Future research on keyboarding skills, varied hardware configurations, and pre-writing and editing activities are suggested. A list of references, two data tables, and two figures are provided. (JB)