An 18-month study examined the impact of word processors on the teaching and learning of writing in an area school on the South Island of New Zealand, with a special focus upon the writing development of 9 primary school children ranging in age from 8 years 11 months to 11 years 8 months. A wide range of data was collected on each pupil, including test scores, responses to questionnaires on writing and the use of the word processor, diary comments, and notes from formal observations. The teachers also maintained diaries, and regular meetings each term were held by the researchers and teachers to discuss progress with the study. Pupils' writing samples, both handwritten and word processed, in draft and in final form, were gathered regularly and analyzed by experienced classroom teachers. Results indicated that most of the case study pupils improved their writing, but the pattern of development varied from pupil to pupil and was inconsistent even for the same pupil. Results also indicated no noticeable improvement in students' spelling because of the availability of the spell checker. Findings suggest that it is unlikely that improvements in pupils' writing could be attributed to use of the word processor. However, word processors may have provided a positive boost for some pupils, and were generally considered in a favorable light by teachers. (Contains 28 references and 2 tables of data. Appendixes contain three questionnaires, instructions to pupils about keeping a diary, and an observation guide for the case study pupils.) (Author/RS)