Introduction: This study aimed to determine the viral agent (s) and their genome burden associated with an aseptic meningitis outbreak that occurred in Yasuj, Iran.Materials And Methods: During April to August 2015, 104 CSF samples from 104 patients under 14 years old admitted to the hospital of Yasuj, Iran, with aseptic meningitis associated clinical signs were collected. 200 μl CSF specimens was prepared for DNA and RNA viral genome extraction each and then subjected to diagnostic Taq-man real time PCR assays for the present of Enteroviruses, HSV, VZV, mumps, measles and rubella in the samples. Results: The majority of them had experienced clinical meningitis sign. Primary laboratory differentiated tests were in favor of viral meningitis. Among a total of 104 patients diagnosed with clinically aseptic meningitis, enterovirus as the most significant viral agent was detected in 53 subjects. However, mumps, HSV and VZV, as the endemic causes of viral meningitis, were detected in 6, 6 and 2 of the affected patients. It was revealed that two HSV and one VZV affected patients were co-infected with enteroviruses. All affected children with relatively variable viral load recovered without any sequels.Conclusion: The present study revealed enterovirus as the main predominant cause of pediatric aseptic meningitis that broke out in Yasuj-Iran. Also, the co-circulation of mumps, HSV and VZV, as the endemic cause during the same aseptic meningitis outbreak, was demonstrated in some cases.