RAS like proto-oncogene B (RALB) gene is located in human chromosome 2 and encodes a GTP-binding protein that belongs to RAS subfamily of the small GTPase superfamily. Recently, RAS signaling pathway has been studied as likely related to ASD. ASD is a complex range of neurodevelopmental disorders. DNA methylation (DNAm) is the most studied epigenetic mark in the mammalian genome. Investigatating the expression level of RALB gene in autistic patients and assessing the relationship between the expression and methylation level of the RALB gene is important to understand its role in Autism. This study included 19 Saudi autistic children and their healthy siblings. Blood was taken to analyze the differential expression of RALB qRT-PCR, and MethyLight assay was used to measure the methylation of CpG sites in the promoter of RALB in order to investigate the association between methylation level and the expression level of RALB. The results showed differential expression patterns for the RALB gene. There was no difference in RALB methylation level of the target region, i.e. the promoter of RALB between autistic and healthy samples. The data suggested a potential role of RALB dysregulation in ASD pathogenesis in the Saudi population. However, questions about the role of RALB in the autism etiology and the probability of RALB expression dysregulations to use as a biomarker for early diagnosis of some ASD cases remain unanswered at present.