Background and Aim: There are many studies about differences between children who stutter and normal pairs in language and cognition domains. On the other hand, a variety of treatment approaches is suggested for stuttering therapy in children. One of them is prolongation (a fluency shaping approach). The aim of the present study is to investigate the effect of prolongation approach on phonological working memory in children with mild and moderate stuttering.

Materials and Methods: Twenty five children who stutter 4 to 6 years old were selected according to inclusion and exclusion criteria, and then non-word repetition test, pre and post treatment were conducted. Intervention process was based on Hedge’s treatment protocol (prolongation). Their score in non word repetition test and stuttering severity was calculated by SSI, pre and post intervention and compared by SPSS soft ware (version 18) And Wilcoxon singed – rank test .

Results: Severity of stuttering was diminished significantly after and before treatment (p<0.05). In non word repetition test, the number of correct non word including single syllable, two syllable and three syllable, pre and post treatment showed significant differences (p<0.05).  There was no relationship between children’s age and their improvement (p>0.05).

Conclusion: Results revealed that prolongation approach had significant effect on improving non word repetition ability and diminishing severity of stuttering. This approach as a form of fluency shaping which usually is based on motor theories had significant effect on increasing phonological working memory capacity.

Key words: Stuttering, Phonological working memory, Fluency shaping, Prolongation approach