Severe combined immunodeficiency is an inherited Primary immunodeficiency PID, which is characterized by the absence or dysfunction of T lymphocytes. Defects in RAG1 and RAG2 are known to cause a TBNK+ form of SCID. Recombinase activating genes RAG1 and RAG2 (OMIM 179615,179616 respectively) are expressed exclusively in lymphocytes and mediate the creation of double-strand. DNA breaks at the sites of recombination and in signal sequences during T− and B− cell receptor gene rearrangement. This study was focused on the effect of nonsynonymous single nucleotide polymorphisms in the function and structure of RAG1& RAG2 genes using In silico analysis. Only nsSNPs and 3’UTR SNPs were selected for computational analysis. Predictions of deleterious nsSNPs were performed by bioinformatics... software. Five damaging nsSNPs (rs112047157, rs61758790, rs4151032, rs61752933, rs75591129) were predicted in RAG1 and two damaging nsSNPs (rs112927992, rs17852002) in RAG2, all of this nsSNPs were found on domain that important in binding and mutation effect in its protein function. Hence it is the first study type of RAG1 and RAG2 analysis. We hope to provide more information that needed to help researchers to do further study in SCID especially in our country where consanguineous marriage is common.