Rabies is an important zoonosis that causes an acute and fatal encephalitis in all mammals. Lyssavirus rabies (RABV) is a negatively polar RNA virus of approximately 12kb that encodes five proteins: nucleoprotein (N), phosphoprotein (P), matrix protein (M or M2), glycoprotein (G) and RNA polymerase (L ). It is one of the oldest infectious diseases of humanity and has a wide range of studies. Despite this, there are paradigms in understanding the stability of RABV, as there is evidence for both its variability and stability, and yet little is known about the evolution of this virus. The present study aimed to identify the genetic stability of RABV. Initially, 21-day-old Swiss albino mice were subjected to 10 successive passages with the standard sample of the RABV Challenge Virus Standard (CVS). The central nervous system (CNS) of each mouse inoculated in each passage was collected and subjected to genetic characterization. To this end, RNA extraction was initially performed (Trizol® Invitrogen method, Carlsbad, CA, USA), reverse transcription followed by polymerase chain reaction (RT-PCR) with primers for the P and G genes. were submitted to sequencing and, finally, to phylogenetic analysis using the sequences obtained in the Bio Edit Sequence Alignment Editor. So far, in the P and G genes, 3 mutations have been identified over the 10 passages. All observed mutations were non-synonymous (modifying the amino acid) and were not maintained across passages. The analyzed genes (G and P) are the genes with the greatest variability, therefore it is expected that mutations occur even in a few passages. Understanding more about the variations of the virus can help in understanding the evolution of rabies, so more studies are essential to clarify these gaps.