Objective: To determine phonological processing in elemantery children with Down syndrome

Materials and Methods: Phonetic test is used to extract phonological processing in 40 child with Down syndrome .They were normal in hearing and oral structure.
Results: There was significant difference between girls and boys in some subgroups of phonological processing. In assimilation, voiceless assimilation in boys and complete assimilation in girls were the most. Nasal assimilation in girls and fricative assimilation in boys were the least. In substitution, the least mean belonged to liquid and nasal substitution in girls and voice ness substitution in boys. In general there was no significant difference between age and phonological awareness however, there was direct correlation between syllable structure and age and reverse correlation between age and stop assimilation.
Conclusion: In addition to 3 groups of phonological processing including: syllable structure, assimilation, and substitution, omission was seen. The difference between girls and boys indicates they are impressed by the phonetic structure of words in different ways. Correlation between age and phonological processing shows phonological errors may be resulted from deviation.