This study examined the effect of the occurrence of homophones in instructional materials on the learning of new vocabulary. Forty-two junior high school seventh graders were randomly assigned to two groups of 21 each. Group one was exposed to a set of six slides that showed sentences using homophonic pairs of words (juxtaposed sentences) and then to another set of six using nonhomophonic pairs of words (substituted sentences). For group two, the order of showing the two sets of slides was reversed. Then all the subjects were given an identical 12-item, multiple-choice test. There was a statistically significant difference between mean scores on juxtaposed and substituted sentence pairs, favoring the substituted sentences. Results indicated an adverse effect from the occurrence of homophones in teaching materials. (Author/AA)