Autism as developmental disorder didnot receive due attention it deserves, from schoolsrnespecially elementary schools. Autistic children are not clearly known in school for thisrnparticular developmental disorder “Autismâ€. The purpose of this research is to investigate therndominant autistic behavior among the school children in Jimma Town.To investigate theserndifferentdevelopmental traits offive (5) children selected for the study were considered againstrnDSM-5 diagnostic criterion and checked for1) presence of symptom at early developmentalrnperiod 2) developmental impairment in three areas, including impairment in social,rncommunication & repetitive behaviors.In process of investigation two levels of screeningrnmethods were usedto select the target groups from 160 students.Fromthis 128 students werernidentified for not having any disability or special needs in the school.From the remaining 32rnstudents, only (five) students (3male and 2 females) showed symptoms of autisticrnspectrumdisorder (ASD). When this was computed from the total population of this study(i.ern1515students),these five children constitute the prevalence of ASD to be 33 out of 10,000 schoolrnage children. Results were discussed and recommendations were forwarded