We evaluated the extent to which prelingually deaf school children who were educated orally made functional use of speech-based codes in reading processes. The study involved two experimental reading tasks: (1) memorizing written words in association with meaning and (2) serial order recall of written word strings. The subjects were 78 school children 6 to 13 years of age. The results revealed a developmental change in the use of coding strategies: up to 9 years of age, most children seem to process written words by means of visual codes; older children tend to differentiate and appear to prefer either a visual or a speech-based strategy. The latter was found to be associated with better performance in reading tasks.