Objective: The purpose of the current research was to study the relation of speech rate of mothers of stuttering children – as a first modeler of speech- with the severity of stuttering in children between ages 5 and 12 years. 
Method: In a field research, 35 mother-stutterer child pairs were selected by convenience sampling from speech therapy clinics in the city of  Tehran . 15 minutes of verbal interaction between child and mother was recorded and transcribed verbatim. Using the Riley index, children were categorized to three groups of mild, moderate and severe stuttering. ANOVA test was used to analyze data. 
Results: There was a significant correlation between the mean scores of maternal speech rate and children's stuttering severity. In addition, there was a significant correlation between mean scores of mother and child speech rate, as well as the mean scores of children's speaking rate and their stuttering severity. 
Conclusion: Results demonstrated that an increase in the maternal speech rate has a positive correlation with stuttering severity and speech rate of children. Also, there is a strong and positive relation between speech rate of children and their stuttering severity.