Background: Acanthamoeba sp, Balamuthia mandrillaris, are a free-living soil amoeba, has emerged as a causative agent of chronic GAE. Methods: The nasal biopsy was sent to our Laboratory of Pathogenic Protozoa and Endosymbionts (LPEP). PCR was processed for Acanthamoeba sp and Balamuthia mandrillaris. It was sequenced and the respective phylogenetic analysis was carried out. Results: We demostrated that the identified species instead correspond to an Acanthamoeba sp. subgentotype T4. Conclusion: The molecular diagnosis shows it to be a case of Acanthamoeba meningocephalitis and not Balamuthia mandrillaris. It is very important to establish the identity of the amoeba using molecular techniques. © 2023 Elsevier B.V., All rights reserved.