Objective: Obtaining the diadochokinetic syllable rates standard among the elementary students in 3, 8, and 19 educational zones in Tehran.
Materials and Methods: 1997 students (980 girls and 1017 boys) randomly selected and examined. Frequency of /pa/, /ta/, /ka/ and /pataka/ in 5 seconds and the number of seconds for producing /pa/, /ta/, /ka/ and /pataka/ for 15 times were recorded for every student.
Results: There is significant difference between means of time and frequency with increasing age. Means of some syllable rates were significantly different between girls and boys.
Conclusion: Mean of syllable frequency was increased and the mean of syllable repetition time was decreased with increasing age. On the whole, boys seems to repeat syllables faster than the girls do.