Introduction: Stuttering is one of the most prevalent speech and language disorders. Symptomatology of stuttering has been surveyed from biological, developmental, environmental, emotional, learning and linguistic viewpoints. Literature shows that "word meaning" as a linguistic feature may influence the frequency of disfluency. Therefore, the aim of this study was to determine the effect of word meaning on disfluency frequency in adult with developmental Stuttering. Materials and Methods: In this cross- sectional descriptive- analytic study, 14 adults who stutter (12 males and 2 females) with the mean age of 24.93 years participated. disfluency frequency was evaluated by asking the subjects to read two lists, one of which contained 60 words and the other 60 non- words. The words were selected based on various Persian syllable structures. The obtained data were statistically analyzed through paired t-test using SPSS software. Results: The results of this study showed that there was significant difference between the frequency of disfluency in word and non-word reading tasks (p<0.05). Conclusion: The findings of this study indicate a significant increase in frequency of disfluency on non- words than on real words. According to the results, it seem that the phonological encoding process of non- word reading must be much more complex than that of real-word reading in the sense that semantic content retrieval (word meaning) is missing in non- word reading.